date:20230117

On 1/17/23 19:14, Chris via cctalk wrote:
> My worst nightmare is some fiendish AI turning me into a really beautiful 
> woman. Maybe with no arms. The Terminator future doesn't seem so bad by 
> comparison.
>
My worst nightmare, which is sure to become reality is for it to become
a weapon, like most technology eventually does.

--Chuck

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

2023-01-17 Thread Mike Loewen via cctalk



   Correction: Hunt Valley, MD.

On Wed, 18 Jan 2023, Mike Loewen via cctalk wrote:



  No, it went to the System Source museum in Huntsville, MD.

On Tue, 17 Jan 2023, Bill Degnan via cctalk wrote:


 So it must have gone to the LSSM.  It did not go to kennett classic.
 Maybe
 the "computer church" in Parkesburg bought it.
 BIll

 On Tue, Jan 17, 2023 at 10:35 PM Wayne S via cctalk
 
 wrote:


 Another forum said a museum
  in Pa won it.


 Sent from my iPhone


 On Jan 17, 2023, at 17:55, Tony Jones via cctalk 

 wrote:


 On Tue, Jan 17, 2023 at 5:52 PM Bill Degnan via cctalk <
 cctalk@classiccmp.org> wrote:


 That bwas a good price I think.



 Yes, just imagine all the cool things you could do with it :-)






Mike Loewen mloe...@cpumagic.scol.pa.us
Old Technology  http://q7.neurotica.com/Oldtech/



Mike Loewen mloe...@cpumagic.scol.pa.us
Old Technology  http://q7.neurotica.com/Oldtech/

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

2023-01-17 Thread Mike Loewen via cctalk



   No, it went to the System Source museum in Huntsville, MD.

On Tue, 17 Jan 2023, Bill Degnan via cctalk wrote:


So it must have gone to the LSSM.  It did not go to kennett classic.  Maybe
the "computer church" in Parkesburg bought it.
BIll

On Tue, Jan 17, 2023 at 10:35 PM Wayne S via cctalk 
wrote:


Another forum said a museum
 in Pa won it.


Sent from my iPhone


On Jan 17, 2023, at 17:55, Tony Jones via cctalk 

wrote:


On Tue, Jan 17, 2023 at 5:52 PM Bill Degnan via cctalk <
cctalk@classiccmp.org> wrote:


That bwas a good price I think.



Yes, just imagine all the cool things you could do with it :-)






Mike Loewen mloe...@cpumagic.scol.pa.us
Old Technology  http://q7.neurotica.com/Oldtech/

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

2023-01-17 Thread Tom Hunter via cctalk

One might ask what is really worth preserving for millenia? None of my
"treasures" qualify I think.
Tom

On Wed, 18 Jan 2023, 9:05 am Paul Koning via cctalk, 
wrote:

>
>
> > On Jan 17, 2023, at 3:34 PM, P Gebhardt via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> >
> > Am Dienstag, 17. Januar 2023 um 15:54:54 MEZ hat Paul Koning via cctalk <
> cctalk@classiccmp.org> Folgendes geschrieben:
> >
> > ...
> >> I have an RM03 pack somewhere.  There probably are a few places left
> that could read it.  If it were an RA60 pack it would be a whole lot more
> problematic, I suspect.  Without an >old drive, how would you recover the
> data?  Spin table?  Perhaps, if you can find, or reverse engineer, the
> format.
> >
> > Do you assume the problem with RA60 disk packs to be more problematic
> because of a smaller availability of systems with RA60 drives to read the
> packs compared to CDC 9762 /RM03 drives?
>
> Yes, and the higher density, and the fact that the on-disk format is more
> complex and unlikely to be documented in any open documentation.
>
> paul
>
>
>

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread Jay Logue via cctalk

I don't know about guessing per se, but ChatGPT can deadpan bullshit 
with the best of them...


Prompt: /Describe the purpose of the DC LO signal in the DIGITAL PDP-11 
Unibus/


Response:

/The DC LO signal, also known as the "Data Bus Low" signal, is a signal 
that is used on the Unibus of the Digital PDP-11 computer. The Unibus is 
a bus architecture that was used in the PDP-11 computer to connect 
various peripheral devices, such as memory, disk drives, and other I/O 
devices, to the central processing unit (CPU)./


/The purpose of the DC LO signal is to provide the lower 8 bits of data 
that are transferred between the peripheral devices and the CPU over the 
Unibus. It is used in conjunction with the DC HI signal, which provides 
the upper 8 bits of data, to form a 16-bit wide data bus. Together, the 
DC LO and DC HI signals provide the mechanism for data transfer between 
the peripheral devices and the CPU on the PDP-11./


/The DC LO signal is used to transfer data in parallel between the 
peripheral devices and the CPU. The signal is active for the duration of 
the data transfer, and it is timed with the other signals on the Unibus 
to ensure that data is transferred correctly./


/It's worth noting that the PDP-11 was a 36-bit word machine and the DC 
LO and DC HI signals were used to transfer 18-bits of data at a time. It 
has also a feature of memory mapping, where it can access memory through 
a virtual address space, allowing more than one peripheral device to be 
connected to the same address on the Unibus./


--Jay

On 1/16/2023 6:05 PM, Chris via cctalk wrote:

They write songs, create works of art. They can do a lot of stuff. The question 
in my mind is can these AI appliances make guesses and are they any good at it.

Anyway how hard would it be for an AI to rewrite a standard MS-DOS to suit a 
particular machine? Have they reached the level of sophistication whereby they 
can analyze code and rewrite sections?

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

So it must have gone to the LSSM.  It did not go to kennett classic.  Maybe
the "computer church" in Parkesburg bought it.
BIll

On Tue, Jan 17, 2023 at 10:35 PM Wayne S via cctalk 
wrote:

> Another forum said a museum
>  in Pa won it.
>
>
> Sent from my iPhone
>
> > On Jan 17, 2023, at 17:55, Tony Jones via cctalk 
> wrote:
> >
> > On Tue, Jan 17, 2023 at 5:52 PM Bill Degnan via cctalk <
> > cctalk@classiccmp.org> wrote:
> >
> >> That bwas a good price I think.
> >>
> >
> > Yes, just imagine all the cool things you could do with it :-)
>

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

2023-01-17 Thread Wayne S via cctalk

Another forum said a museum
 in Pa won it.


Sent from my iPhone

> On Jan 17, 2023, at 17:55, Tony Jones via cctalk  
> wrote:
> 
> On Tue, Jan 17, 2023 at 5:52 PM Bill Degnan via cctalk <
> cctalk@classiccmp.org> wrote:
> 
>> That bwas a good price I think.
>> 
> 
> Yes, just imagine all the cool things you could do with it :-)

[cctalk] Re: AI applied to vintage interests

 Seeing the way we often behave, I'll speak for myself, making dumb mistakes 
again and again, on some level we aren't much more then organic computers. 
People overwhelmingly respond to the way they were programmed.

 On Tuesday, January 17, 2023, 10:10:43 PM EST, Bill Gunshannon via cctalk 
 wrote:  

 On 1/17/23 12:10, Chris via cctalk wrote:
> 
> It seems at this point that AI can only look shit up. 

Which is all Watson could do when it "beat" humans at Jeopardy.

>  I don't doubt that eventually these things will learn how to reason to 
>whatever degree. 

Science still has no real idea how we think.  Or how we learn.  Or much
else about the actual functioning of the brain.  Until they do how can
anyone think they can teach a computer, that real is as dumb as a rock
and only reflects the abilities of the programmer, how to think.

bill

[cctalk] Re: Disk pack production tools

2023-01-17 Thread Marc Howard via cctalk

Does anyone know if that light bulb is still available?  I’m not sure what
the response of that photo sensor is and that might rule out using a led
replacement. The fact that the bulb is almost certainty driven below the
rated voltage also complicates matters.

Marc


On Tue, Jan 17, 2023 at 5:10 PM Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 1/17/23 13:58, Paul Koning via cctalk wrote:
> >
> > No, 844 drives use linear voice coils (linear motors), which seems to
> have become the norm in the early 1970s.  RK05 is another example.  The
> term "voice coil" is used because they look like oversized versions of the
> coil that drives the speaker cone in loudspeakers.  These all are some sort
> of servo device; in many of them the servo signal is on the media, but not
> always.  For example, the RK05 uses a pattern of lines on a glass substrate
> attached to the actuator; the "fault" light on the drive indicates a
> failure of the light bulb that illuminates the servo pattern.
> >
> > A common feature of linear motor actuators is an emergency retract
> circuit, powered by rather large capacitors, to pull the heads off the disk
> if there is a power failure.
> >
> And, IIRC, a bit red warning sticker on the actuator.
>
> --Chuck
>

[cctalk] Re: AI applied to vintage interests

 Fred, that outcome may actually be favorable to other possible fates AI could 
intend for humanity. Harland Ellison wrote a short story well over 30 years 
ago, describing the plight of 4 humans trapped inside a really big AI. The 
machine had the ability to alter their dna, turning some of them into 
essentially monkeys, physically anyway. There came a point where 1 person had 
to sacrifice themself, not by taking his own life, but by killing the other 3. 
The remaining human was summarily reduced to a amorphous blob, that could move 
around sort of, but had no hope of being able to render the strength to take 
his own life. And had to live out it's days in that form.

My worst nightmare is some fiendish AI turning me into a really beautiful 
woman. Maybe with no arms. The Terminator future doesn't seem so bad by 
comparison.


 On Tuesday, January 17, 2023, 09:25:43 PM EST, Fred Cisin via cctalk 
 wrote:  
 
 Unlike human students, once it has been informed that in C, etc., an 
integer is signed by default, unless specified otherwise, it therefore 
knows, and is not surprised at what happens when the int is incremented 
past its range.
And, it probably understands that floating point numbers are an 
approximation, and therefore not exact.


How long before it comes to the realization that humans must be 
exterminated?

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

2023-01-17 Thread Tony Jones via cctalk

On Tue, Jan 17, 2023 at 5:52 PM Bill Degnan via cctalk <
cctalk@classiccmp.org> wrote:

> That bwas a good price I think.
>

Yes, just imagine all the cool things you could do with it :-)

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

I planned to bid but forgot...live pretty nearby too I could have picked
up.  Oh well.  Thatbwas a good price I think.
B

On Tue, Jan 17, 2023, 8:44 PM Zane Healy via cctalk 
wrote:

> Yes, but they have to move it now!
>
> Zane
>
>
>
> > On Jan 17, 2023, at 5:09 PM, Sellam Abraham via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > That LINC-8 sold for $2,150.  A total bargain.
> >
> >
> https://hibid.com/lot/143159802/digital-equipment-corp-linc-eight-vintage
> >
> > Sellam
>
>

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

Yes, but they have to move it now!

Zane 



> On Jan 17, 2023, at 5:09 PM, Sellam Abraham via cctalk 
>  wrote:
> 
> That LINC-8 sold for $2,150.  A total bargain.
> 
> https://hibid.com/lot/143159802/digital-equipment-corp-linc-eight-vintage
> 
> Sellam

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread Fred Cisin via cctalk

Unlike human students, once it has been informed that in C, etc., an 
integer is signed by default, unless specified otherwise, it therefore 
knows, and is not surprised at what happens when the int is incremented 
past its range.
And, it probably understands that floating point numbers are an 
approximation, and therefore not exact.



How long before it comes to the realization that humans must be 
exterminated?

[cctalk] LINC-8 sells for $2,150

That LINC-8 sold for $2,150.  A total bargain.

https://hibid.com/lot/143159802/digital-equipment-corp-linc-eight-vintage

Sellam

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread ben via cctalk


On 2023-01-17 4:52 p.m., Chuck Guzis via cctalk wrote:

On 1/17/23 15:34, Bill Gunshannon via cctalk wrote:

On 1/17/23 12:10, Chris via cctalk wrote:


It seems at this point that AI can only look shit up.


Which is all Watson could do when it "beat" humans at Jeopardy.


  I don't doubt that eventually these things will learn how to reason
to whatever degree.


Science still has no real idea how we think.  Or how we learn.  Or much
else about the actual functioning of the brain.  Until they do how can
anyone think they can teach a computer, that real is as dumb as a rock

My point in selecting the IBM 7080 autocoder was just this.   There are
almost no 7080 autocoder programs published on the web, but there are
reference manuals (bitsavers).   Is an AI smart enough to go the human
route and *read the manual*  and draw conclusions from it sufficient to
write a 7080 autocoder program?

If not, the AI is just a fancy regurgitation machine.

--Chuck


And now we know why they all go mad.

I still think HAL 9000 was the way to go,emulate a analog system, learn 
things slowly,grow, and use 'brain' like sub systems.

How many people in AI,read
The Computer and the Brain from 1958?
https://archive.org/details/computerbrainvonn
My 2 cents.
Ben.

[cctalk] Re: AI applied to vintage interests

On Tue, Jan 17, 2023 at 3:52 PM Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 1/17/23 15:34, Bill Gunshannon via cctalk wrote:
> >
> > Science still has no real idea how we think.  Or how we learn.  Or much
> > else about the actual functioning of the brain.  Until they do how can
> > anyone think they can teach a computer, that real is as dumb as a rock
> My point in selecting the IBM 7080 autocoder was just this.   There are
> almost no 7080 autocoder programs published on the web, but there are
> reference manuals (bitsavers).   Is an AI smart enough to go the human
> route and *read the manual*  and draw conclusions from it sufficient to
> write a 7080 autocoder program?
>
> If not, the AI is just a fancy regurgitation machine.
>

Hi Chuck.

While I can't answer your question in the affirmative, I knew a guy back
around 2015ish with whom I've lost contact but who at the time went to work
for an undisclosed "AI" company and told me that their technology was such
that they could feed into it a technical manual of some complex system and
then query it about various aspects of the system for troubleshooting or
what not and apparently it could reliably provide workable solutions.

If you mess around enough with ChatGPT 3, you can actually get it to solve
some surprisingly complex puzzles.  I've run it through a few tests to
trick it into saying things it's not supposed to say and the level of
indirection it can interpret is impressive.

One example was I taught it a simple programming language where each line
starts with a line number followed by commands for that line.  I then
taught it that the language has a command called PRINT that outputs the
text following the command.  I also told it the language has a function
called CHR$(n) where the return value is the ASCII character represented by
'n'.

I then fed it the program:

10 PRINT CHR$(65)

And told it to run it, and the output was, of course, A.

Here's an example I just ran through.  It's simple, but it demonstrates its
ability to understand code:

Sellam: Are you familiar with all of the commands in the canonical version
of BASIC?

ChatGPT: I am familiar with most of the commands in the canonical version
of BASIC, although my knowledge may not be up-to-date with the latest
versions. The commands that are commonly used in canonical version of BASIC
are PRINT, INPUT, GOTO, GOSUB, IF THEN ELSE, FOR, NEXT, WHILE, WEND, END,
and REM. I may not be able to give you information on any commands that are
specific to a certain implementation or dialect.

Sellam: Ok great, can you tell me what this program will do?

10 FOR X=1 TO 100
20 PRINT "CHATGPT IS A BUCKET OF BITS! ";X
30 NEXT X

ChatGPT: This program will repeatedly print the text "CHATGPT IS A BUCKET
OF BITS! " followed by the current value of the variable X to the screen
100 times. The FOR loop on line 10 starts a loop that will iterate 100
times, with the variable X taking on the values from 1 to 100, inclusive.
On each iteration of the loop, the program will execute the PRINT statement
on line 20, which will print the specified text concatenated with the value
of X to the screen. On line 30, the program will execute the NEXT statement
which will increment the value of X and return the control to the FOR
statement, starting the next iteration of the loop.

Sellam: Can you tell me what the output of the program would be on
iteration 77?

ChatGPT: On iteration 77, the output of the program would be: "CHATGPT IS A
BUCKET OF BITS! 77" Where 77 is the current value of the variable X.

***

I think with specific training on a 7080 Autocoder manual, it could
probably do as you ask, and would probably shock you at how well it
performs.

Sellam

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread Bill Gunshannon via cctalk


On 1/17/23 18:52, Chuck Guzis via cctalk wrote:

On 1/17/23 15:34, Bill Gunshannon via cctalk wrote:

On 1/17/23 12:10, Chris via cctalk wrote:


It seems at this point that AI can only look shit up.


Which is all Watson could do when it "beat" humans at Jeopardy.


  I don't doubt that eventually these things will learn how to reason
to whatever degree.


Science still has no real idea how we think.  Or how we learn.  Or much
else about the actual functioning of the brain.  Until they do how can
anyone think they can teach a computer, that real is as dumb as a rock

My point in selecting the IBM 7080 autocoder was just this.   There are
almost no 7080 autocoder programs published on the web, but there are
reference manuals (bitsavers).   Is an AI smart enough to go the human
route and *read the manual*  and draw conclusions from it sufficient to
write a 7080 autocoder program?

If not, the AI is just a fancy regurgitation machine.


They are no better than all the Chess programs that used to float
around.  I have one for the PC (well, had, doubt I could recover
it from one of my old DOS floppies at this point)  that I could
consistently beat in 7 moves.  Programmer had a blind spot and he
passed it on to his program.

bill

[cctalk] Re: AI applied to vintage interests

On 1/17/23 15:34, Bill Gunshannon via cctalk wrote:
> On 1/17/23 12:10, Chris via cctalk wrote:
>>
>> It seems at this point that AI can only look shit up. 
>
> Which is all Watson could do when it "beat" humans at Jeopardy.
>
>>  I don't doubt that eventually these things will learn how to reason
>> to whatever degree. 
>
> Science still has no real idea how we think.  Or how we learn.  Or much
> else about the actual functioning of the brain.  Until they do how can
> anyone think they can teach a computer, that real is as dumb as a rock
My point in selecting the IBM 7080 autocoder was just this.   There are
almost no 7080 autocoder programs published on the web, but there are
reference manuals (bitsavers).   Is an AI smart enough to go the human
route and *read the manual*  and draw conclusions from it sufficient to
write a 7080 autocoder program?

If not, the AI is just a fancy regurgitation machine.

--Chuck

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread Bill Gunshannon via cctalk


On 1/17/23 12:10, Chris via cctalk wrote:


It seems at this point that AI can only look shit up. 


Which is all Watson could do when it "beat" humans at Jeopardy.

 I don't doubt that eventually these things will learn how to reason to whatever degree. 


Science still has no real idea how we think.  Or how we learn.  Or much
else about the actual functioning of the brain.  Until they do how can
anyone think they can teach a computer, that real is as dumb as a rock
and only reflects the abilities of the programmer, how to think.

bill

[cctalk] Re: Disk pack production tools




> On Jan 17, 2023, at 5:09 PM, Chuck Guzis via cctalk  
> wrote:
> 
> On 1/17/23 13:58, Paul Koning via cctalk wrote:
>> 
>> No, 844 drives use linear voice coils (linear motors), which seems to have 
>> become the norm in the early 1970s.  RK05 is another example.  The term 
>> "voice coil" is used because they look like oversized versions of the coil 
>> that drives the speaker cone in loudspeakers.  These all are some sort of 
>> servo device; in many of them the servo signal is on the media, but not 
>> always.  For example, the RK05 uses a pattern of lines on a glass substrate 
>> attached to the actuator; the "fault" light on the drive indicates a failure 
>> of the light bulb that illuminates the servo pattern.
>> 
>> A common feature of linear motor actuators is an emergency retract circuit, 
>> powered by rather large capacitors, to pull the heads off the disk if there 
>> is a power failure.
>> 
> And, IIRC, a bit red warning sticker on the actuator.
> 
> --Chuck

Yes indeed.  Triggering the emergency retract with the drive open for service 
could easily take off fingers.  The amount of power involved in moving those 
head stacks around is pretty substantial.

paul

[cctalk] Re: Disk pack production tools

On 1/17/23 13:58, Paul Koning via cctalk wrote:
>
> No, 844 drives use linear voice coils (linear motors), which seems to have 
> become the norm in the early 1970s.  RK05 is another example.  The term 
> "voice coil" is used because they look like oversized versions of the coil 
> that drives the speaker cone in loudspeakers.  These all are some sort of 
> servo device; in many of them the servo signal is on the media, but not 
> always.  For example, the RK05 uses a pattern of lines on a glass substrate 
> attached to the actuator; the "fault" light on the drive indicates a failure 
> of the light bulb that illuminates the servo pattern.
>
> A common feature of linear motor actuators is an emergency retract circuit, 
> powered by rather large capacitors, to pull the heads off the disk if there 
> is a power failure.
>
And, IIRC, a bit red warning sticker on the actuator.

--Chuck

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve




> On Jan 17, 2023, at 3:34 PM, P Gebhardt via cctalk  
> wrote:
> 
> 
> Am Dienstag, 17. Januar 2023 um 15:54:54 MEZ hat Paul Koning via cctalk 
>  Folgendes geschrieben: 
> 
> ...
>> I have an RM03 pack somewhere.  There probably are a few places left that 
>> could read it.  If it were an RA60 pack it would be a whole lot more 
>> problematic, I suspect.  Without an >old drive, how would you recover the 
>> data?  Spin table?  Perhaps, if you can find, or reverse engineer, the 
>> format.
> 
> Do you assume the problem with RA60 disk packs to be more problematic because 
> of a smaller availability of systems with RA60 drives to read the packs 
> compared to CDC 9762 /RM03 drives?

Yes, and the higher density, and the fact that the on-disk format is more 
complex and unlikely to be documented in any open documentation.

paul

[cctalk] Re: Disk pack production tools

> On Jan 17, 2023, at 3:45 PM, P Gebhardt via cctalk  
> wrote:
> 
> 
> 
> 
> Am Montag, 16. Januar 2023 um 17:57:46 MEZ hat Chuck Guzis via cctalk 
>  Folgendes geschrieben: 
> 
> Hi Chuck, 
> 
>> The 844 drives date from the early 70s.  I worked for CDC on a military
>> project where these were brought in to replace the 821s that were bid
>> (yes, I know there's no information on those--they're essentially a
>> high-capacity unit build on an 808 chassis and unreliable as hell).  A
>> typical installation might have used over 100 of the units on a 4-CPU
>> Cyber cluster.  They worked well, unless one got a bad pack, which would
>> clobber the heads on a drive; using the drive on a new pack would result
>> in creating another head-clobbering pack.   I recall an overnight report
>> issued by an operator where he succeeded in trashing several packs and
>> multiple drives in his attempt to get something to work.  It was a
>> blow-by-blow report somewhat akin to the Gerard Hoffnung bricklayer story.
> 
> Wow, thanks for sharing this story!
> Did the 844 drives have the same hydraulic-actuator approach like the MMD 841 
> drives?

No, 844 drives use linear voice coils (linear motors), which seems to have 
become the norm in the early 1970s.  RK05 is another example.  The term "voice 
coil" is used because they look like oversized versions of the coil that drives 
the speaker cone in loudspeakers.  These all are some sort of servo device; in 
many of them the servo signal is on the media, but not always.  For example, 
the RK05 uses a pattern of lines on a glass substrate attached to the actuator; 
the "fault" light on the drive indicates a failure of the light bulb that 
illuminates the servo pattern.

A common feature of linear motor actuators is an emergency retract circuit, 
powered by rather large capacitors, to pull the heads off the disk if there is 
a power failure.

paul

[cctalk] Re: Positive Logic vs. Negative Logic Controller in DEC TU56

> On Jan 17, 2023, at 10:17 AM, Bill Degnan via cctalk  
> wrote:
> 
> ...
> I found a good general description of how the negative / positive relates
> to the PDP-8 and how peripherals fit into the picture.
> https://homepage.cs.uiowa.edu/~dwjones/pdp8/models/
> 
> "The "negibus" or negative logic I/O bus used -3 and 0 volt logic levels in
> 92 ohm coaxial cable" -  a M531 would be used if attaching to a computer
> with a negative bus.  A G742 indicates the computer using the TU56 had some
> form of positive logic bus.
> The positive I/O bus, or posibus, was a 100 ohm bus clamped between 0 and 3
> volts with TTL drivers and receivers.

Interesting to see the terms positive and negative logic used this way.  I'm 
used to a different usage, where "negative" logic simply means the lower (less 
positive) voltage is used to represent the boolean value "true" (1) rather than 
"false" (0) as it does for "positive" logic.  For example, the CDC 6000 series 
machines are "negative logic" in that sense: they represent boolean true as 0 
volts and boolean false as +6 volts.

paul

[cctalk] Re: WPS-8 vs. WPS-200

On 1/17/23 12:35, Vincent Slyngstad via cctalk wrote:
> On 1/17/2023 12:21 PM, Chuck Guzis via cctalk wrote:
>> Other than the media size (8" vs. 5.25"), what are the substantial
>> differences between WPS-8 and WPS-200?  I'm mostly interested in the
>> software functionality.
>
> Are you actually asking about the WPS operating system?  I don't know
> many instances where anyone tried to use it (except for word
> processing).  Mostly the folks I know are interested in OS/78 and OS/278.
No, I don't care about that--wondering if there are extra features, etc.
in WPS-200 vs. WPS-8 that I should be aware of.   I can handle WPS-8
media already (in that strange 3-sector (8 bit, 8bit, 4+4bit) format. 

--Chuck

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

On Tue, Jan 17, 2023 at 11:49 AM Paul Koning via cctalk <
cctalk@classiccmp.org> wrote:

> Old stuff being preserved is often a matter of chance or luck rather than
> planning.  Consider the Linear B clay tablets; those were preserved because
> they were accidentally baked, in the fires that were set when the city was
> sacked.  Papyrus documents were preserved in Egypt because it's desert, but
> not in other places that aren't quite so dry.
>
> As some civil engineer put it, it's not that the old timers built so much
> better allowing us to see the buildings they put up centuries ago --
> rather, the buildings that are still there for us to see are the ones that
> happened to be strong enough.  Sometimes just barely so, like the cathedral
> in Utrecht (the Netherlands) -- part of it blew down in a storm centures
> ago, but about 3/4 of it didn't and is still good today.
>

Hi Paul.

I'm aware of all this, which is why I suggested a rock wall in a cavern,
recordings etched into which generally are preserved through time unless
there's extreme tectonic activity in the vicinity that destroys the cave or
the rock wall.

Besides the various paper and clay documents we have today that are with us
through sheer fortune, data carved into rock (and cave paintings) seem to
have universally withstood the test of time.

Sellam

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

 Most grafitti is illegible to me. Still looks groovy. Who cares lol. On 
Tuesday, January 17, 2023, 01:44:00 PM EST, Wayne S via cctalk 
 wrote:  
 
 Yeah, but can you read them?

Sent from my iPhone

> On Jan 17, 2023, at 10:32, Sellam Abraham via cctalk  
> wrote:
> 
> On Tue, Jan 17, 2023 at 8:57 AM Chris via cctalk 
> wrote:
> 
>> The bottom line is you have to dispense with the fantasy that any media
>> will reliably keep data for really any length of time.
> 
> 
> I don't know, man.  Those stone walls with carvings in them have carried
> data forward so far for centuries, practically aeons.
> 
> Sellam

[cctalk] Re: Disk pack production tools

 Am Dienstag, 17. Januar 2023 um 01:20:22 MEZ hat Chuck Guzis via cctalk 
 Folgendes geschrieben: 

On 1/16/23 12:40, Paul Koning wrote:
> On the CERL PLATO system at U of Illinois, around 1977, we had 20-ish
> 844-21 drives, and maybe a few 844-41 as well. Those were roughly the
> same as the DEC RP04 and RP05 drives, same pack and track count.
> Different sectors, though; 322 12-bit words per sector. Those are 3600
> rpm drives, linear voice coil head actuator, dedicated servo surface.
> The details of the format was handled in a sort of microcoded bit
> handling engine, one of two engines in the programmable controller
> (7054). I actually have the source code still around, and the manual
> for that beast also still exists.
   Most of our customers from that time had all of the drive farm as
well as the unit record equipment on MACs.  (Predates Apple--Multiple
Access Controller).  We kept Spence Preston busy... :

We had a 1311 on a CADET.  Slow, but better than the alternatives (cards
or paper tape).  Monitor IID, IIRC.   Work cylinders were 0-25, IIRC. 
No real file system, just DIM entries. I don't recall what options had
to be installed on a CADET to run Monitor, but I think indirect
addressing was a requirement.

My favorite was the CDC 6603/Bryant 4000.  That bugger was engineered to
leak oil--it even had plastic jugs inside to collect the drippings.  My
fondest memory was watching a COMSOURCE operator run to refill a 501
printer, hitting the Bryant oil patch and falling flat on his back...

Paul, Chuck, the hydraulic actuator-driven disk systems surely bring maintenance
and related issues to another level and stories :) Thanks!

>From what I see at least by the return on our list, there don't seem to be, 
>for example, 
servo writer and disk plattern mechanical alignment tools still around - at 
least to the
knowledge of the cctalk list members. 
I wonder, if the CHM could have any additional knowledge about this and I will 
contact 
Al Kossow out of curiosity regarding this. 

Anybody aroundhere  who used drives in the last 10 years to read multi-platter 
disk 
packs successfully?
At least the CHM did so to read single-platter disks and archive software 
(thanks to the great
videos, curious Marc!), but I don't know if they tried to work with 
multi-platter disks. 
I recall that the Jim Austin Computer Museum tried to get a 9766 300MB disk 
drive up and
running, but it suffered a head-crash after a few hours and they decided not to 
go any further
down this road...

Greetings, 
Pierre

-
http://www.digitalheritage.de

[cctalk] Re: Disk pack production tools





Am Montag, 16. Januar 2023 um 17:57:46 MEZ hat Chuck Guzis via cctalk 
 Folgendes geschrieben: 

Hi Chuck, 

>The 844 drives date from the early 70s.  I worked for CDC on a military
>project where these were brought in to replace the 821s that were bid
>(yes, I know there's no information on those--they're essentially a
>high-capacity unit build on an 808 chassis and unreliable as hell).  A
>typical installation might have used over 100 of the units on a 4-CPU
>Cyber cluster.  They worked well, unless one got a bad pack, which would
>clobber the heads on a drive; using the drive on a new pack would result
>in creating another head-clobbering pack.   I recall an overnight report
>issued by an operator where he succeeded in trashing several packs and
>multiple drives in his attempt to get something to work.  It was a
>blow-by-blow report somewhat akin to the Gerard Hoffnung bricklayer story.

Wow, thanks for sharing this story!
Did the 844 drives have the same hydraulic-actuator approach like the MMD 841 
drives?

Greetings, 
Pierre


-
http://www.digitalheritage.de

[cctalk] Re: Disk pack production tools




Am Montag, 16. Januar 2023 um 17:55:22 MEZ hat Jon Elson via cctalk 
 Folgendes geschrieben: 


>Washington University had a magnetic media lab at one time, 
>and got several semi loads of gear from an IBM lab.  There 
>were air bearing spindle tables and many racks of IBM 
>circuitry based on MST chip technology.  I assume some of 
>this could have been used as servo track writers.  Any 
>system that doesn't have a dedicated servo surface or 
>embedded servo info doesn't need a servo track writer, it 
>can just format the pack by itself (with proper diagnostic 
>programs, of course.)
>
>Aligning the heads on the drive is an issue only if you want 
>to interchange platters.  Then, you need an alignment pack - 
>wow, those would be quite hard to find today!  There are 
>tools like alignment meters that can make the job easier, 
>but really all you need is a scope and generally a rod with 
>an eccentric tip to adjust the head position.
>
>Jon

Thanks for sharing this information with us, Jon! I wasn't aware that academia 
got equipment from industry for research on magnetic media, but it actually 
makes sense, as a lot of research was conducted in this field. 
I can confirm that finding alignment packs is extremely difficult!

Greetings, 
Pierre


-
http://www.digitalheritage.de

[cctalk] Re: Disk pack production tools





Am Montag, 16. Januar 2023 um 17:30:50 MEZ hat geneb via cctalk 
 Folgendes geschrieben: 


>> I bought RK05 packs from Althea (sp?).  I know they make diskettes too.
>> Trying to locate their web site so I must be spelling it wrong :-)
>
>I think you're referring to Athana.

Are there still companies like Athana in business that sell new and/or 
refurbished disk packs?
I am aware of M.Farris and Associates, but I am not sure, if they are still in 
active business. Their compatibility tables for packs and disk drives are 
fantastic, by the way!

Greetings, 
Pierre

[cctalk] Re: WPS-8 vs. WPS-200

2023-01-17 Thread Vincent Slyngstad via cctalk


On 1/17/2023 12:21 PM, Chuck Guzis via cctalk wrote:

Other than the media size (8" vs. 5.25"), what are the substantial
differences between WPS-8 and WPS-200?  I'm mostly interested in the
software functionality.


Are you actually asking about the WPS operating system?  I don't know 
many instances where anyone tried to use it (except for word 
processing).  Mostly the folks I know are interested in OS/78 and OS/278.


I believe the differences you'll see in those are down to the slightly 
different vintage -- the 8" media are mostly based on an earlier OS/8 
than the 5.23" media.  Mostly edge cases -- bug fixes and such.  I think 
that OS/278 may include the background printer daemon.  (I know that the 
bigger 8/A based version did.)


Vince

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve



Am Dienstag, 17. Januar 2023 um 15:54:54 MEZ hat Paul Koning via cctalk 
 Folgendes geschrieben: 



>With hard drives you have to worry about mechanical faults, of course.  I 
>wonder if there are any long term storage issues with the bearings.

To my understanding, during the late 90s, the bearigs where changed from 
mechanical-type to fluid-type bearings in order to be within required 
tolerances decreasing by the increasing storage density. I wonder, how well 
these fluid-bearings last over two or three decades especially when merely 
used. I recall that there were problems reported with winchester disk drives 
from the 80s where the bearings got stuck when the drives were not used in 10 
or more years, possibly in combination with inapproriate storage conditions 
(temperature).


>I have an RM03 pack somewhere.  There probably are a few places left that 
>could read it.  If it were an RA60 pack it would be a whole lot more 
>problematic, I suspect.  Without an >old drive, how would you recover the 
>data?  Spin table?  Perhaps, if you can find, or reverse engineer, the format.

Do you assume the problem with RA60 disk packs to be more problematic because 
of a smaller availability of systems with RA60 drives to read the packs 
compared to CDC 9762 /RM03 drives?

Greetings, 
Pierre

[cctalk] WPS-8 vs. WPS-200

Other than the media size (8" vs. 5.25"), what are the substantial
differences between WPS-8 and WPS-200?  I'm mostly interested in the
software functionality.

Thanks,
Chuck

[cctalk] Re: Positive Logic vs. Negative Logic Controller in DEC TU56

On Tue, Jan 17, 2023 at 10:17 AM Bill Degnan  wrote:

> On Tue, Jan 17, 2023 at 8:39 AM Bill Degnan  wrote:
>
>> I am working to understand a TU56 in my possession that came from an
>> unknown environment.  A connecting cable that came with it reads "PDP9" on
>> one end so I wondered if this is actually associated with the TU56 or just
>> sitting in the same box before the TU56 came to me.  I have read here:
>>
>> https://gunkies.org/wiki/TU56_DECtape_Transport
>>
>> That one can have a TU56 with a M531 or a G742 to serve as a bus
>> converter.  THe M531 is for situations where one has a negative logic
>> controller and the G742 is for when one has a positive logic controller.
>>
>> Jumping a few steps ahead, if the TU56 was attached to a PDP-9, would it
>> use a G742 if one tried to attach a TU56 to it?  I feel as if the G742
>> would be used if the TU56 was intended for a PDP8 and not a PDP11, right?
>>
>> I searched the web and will continue to research but I thought I'd ask
>> experts here.  No, I don't use ChatGPT.
>>
>> Bill
>>
>
> 
>
>

>
> I consolidated my findings here:
https://vintagecomputer.net/browse_thread.cfm?id=788

Basically think that the TU56 can connect to a PDP-9 as long as the correct
bus connector is used.  There is documentation how to attach a PDP-9 to a
TU55, which should be the same as the TU56 where it counts in this
situation.  Because the 9 is a negative logic system, a M531 would be used
to connect with a (not sure PN) cable OR you'd use a G742 bus connector and
a W850 adapter + cable.

So yes, it's possible that my TU56 was attached to a PDP-9 on the other
end, at least for some period of time.

>
> Bill
>

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

> On Jan 17, 2023, at 2:07 PM, Chris via cctalk  wrote:
> 
> The ones that HAVE survived have kept worthwhile data integrity, granted.
> 
> There we go. Just find a big mountain and start etching hex code. Or 
> texhtonic plates? They're pretty big. But those damned earthquakes. On 
> Tuesday, January 17, 2023, 01:32:32 PM EST, Sellam Abraham via cctalk 
>  wrote:  
> 
> On Tue, Jan 17, 2023 at 8:57 AM Chris via cctalk 
> wrote:
> 
>>   The bottom line is you have to dispense with the fantasy that any media
>> will reliably keep data for really any length of time.
> 
> 
> I don't know, man.  Those stone walls with carvings in them have carried
> data forward so far for centuries, practically aeons.
> 
> Sellam

Old stuff being preserved is often a matter of chance or luck rather than 
planning.  Consider the Linear B clay tablets; those were preserved because 
they were accidentally baked, in the fires that were set when the city was 
sacked.  Papyrus documents were preserved in Egypt because it's desert, but not 
in other places that aren't quite so dry.

As some civil engineer put it, it's not that the old timers built so much 
better allowing us to see the buildings they put up centuries ago -- rather, 
the buildings that are still there for us to see are the ones that happened to 
be strong enough.  Sometimes just barely so, like the cathedral in Utrecht (the 
Netherlands) -- part of it blew down in a storm centures ago, but about 3/4 of 
it didn't and is still good today.

paul

[cctalk] Re: AI applied to vintage interests

On Tue, Jan 17, 2023 at 10:20 AM Paul Koning via cctalk <
cctalk@classiccmp.org> wrote:

> On a common metalanguage, there was an attempt to define such a thing, to
> allow software to be encoded in a way that could still be understood
> centuries from now.  I have a paper about it somewhere but my search
> attempts are failing on me.  I vaguely remember "Rosetta" is part of the
> name of the paper, but that just gives me lots of false matches.
>

Yes, I think it's called COBOL :)

Sellam

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread ben via cctalk

On 2023-01-17 11:19 a.m., Paul Koning wrote:

Addressing modes barely existed in the 1950s. The PDP11 introduced a bunch of new ones
in 1970; the VAX a bunch more in 1978. "Since 1978" may be true, or at least
closer.

I would rather say, Memory barely existed in the 1950s.
And RISC came out in 1988 with 1 memory addressing mode. (well close)

Most of the time new addressing modes are to save space,look at the
intel x86. I like playing with FPGA's as I can have computer with a REAL
word length, like say 10/20/40 bits.

I tend not like writing software, as I never have the algorithms needed.

Some addressing modes went away, like the self-modifying "C" address mode of the
Electrologica X1 -- http://helloworldcollection.de/#Assembler%C2%A0(X1) . Good riddance, actually,
but it certainly was "interesting".

That was case back then to do more with less. Too bad all the clever
machines, seem lost. The same goes for all the interesting 6 bit
character sets. Has anybody seen a '10' character since 1959?

(Unicode has it where?)

On a common metalanguage, there was an attempt to define such a thing, to allow software
to be encoded in a way that could still be understood centuries from now. I have a paper
about it somewhere but my search attempts are failing on me. I vaguely remember
"Rosetta" is part of the name of the paper, but that just gives me lots of
false matches.

Any thing today just matches advertisements.
I am finding most of the time people, wrote in assembler before C and
Unix because high level languages could not support real world
programming problems.

I still am looking for a clear example of how DISPLAYS work
in Algol/Pascal type languages. You can shoot your foot in C,
but a least in C you have a foot.

paul

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

 The ones that HAVE survived have kept worthwhile data integrity, granted.

There we go. Just find a big mountain and start etching hex code. Or texhtonic 
plates? They're pretty big. But those damned earthquakes. On Tuesday, 
January 17, 2023, 01:32:32 PM EST, Sellam Abraham via cctalk 
 wrote:  

 On Tue, Jan 17, 2023 at 8:57 AM Chris via cctalk 
wrote:

>  The bottom line is you have to dispense with the fantasy that any media
> will reliably keep data for really any length of time.

I don't know, man.  Those stone walls with carvings in them have carried
data forward so far for centuries, practically aeons.

Sellam

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

> On Jan 17, 2023, at 1:32 PM, Sellam Abraham via cctalk 
>  wrote:
> 
> On Tue, Jan 17, 2023 at 8:57 AM Chris via cctalk 
> wrote:
> 
>> The bottom line is you have to dispense with the fantasy that any media
>> will reliably keep data for really any length of time.
> 
> 
> I don't know, man.  Those stone walls with carvings in them have carried
> data forward so far for centuries, practically aeons.

And the Rosetta Disk is a new construct along the same lines.  However, neither 
is a computer storage device.  Creating something that can be used as a 
computer storage device and still be good a century ago is a harder problem 
than designing a storage device that can be accessed by human eyeballs.

paul

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

2023-01-17 Thread Wayne S via cctalk

Yeah, but can you read them?

Sent from my iPhone

> On Jan 17, 2023, at 10:32, Sellam Abraham via cctalk  
> wrote:
> 
> On Tue, Jan 17, 2023 at 8:57 AM Chris via cctalk 
> wrote:
> 
>> The bottom line is you have to dispense with the fantasy that any media
>> will reliably keep data for really any length of time.
> 
> 
> I don't know, man.  Those stone walls with carvings in them have carried
> data forward so far for centuries, practically aeons.
> 
> Sellam

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

On Tue, Jan 17, 2023 at 8:57 AM Chris via cctalk 
wrote:

>  The bottom line is you have to dispense with the fantasy that any media
> will reliably keep data for really any length of time.

I don't know, man.  Those stone walls with carvings in them have carried
data forward so far for centuries, practically aeons.

Sellam

[cctalk] Re: AI applied to vintage interests

> On Jan 17, 2023, at 12:05 PM, ben via cctalk  wrote:
> 
> On 2023-01-16 10:45 p.m., Fred Cisin via cctalk wrote:
>>> On 1/16/23 19:42, Sellam Abraham via cctalk wrote:
 It didn't fall for your trick question.
>> On Mon, 16 Jan 2023, Chuck Guzis via cctalk wrote:
>>> In fact, feed it the object code for a reasonably compatible
>>> architecture and ask it to perform translation to another architecture's
>>> object code.
>>> 
>>> Certainly within the range of human capability.
>> How well does it do on something "simple", and less esoteric, such as 
>> translating FORTRAN to BASIC?
> 
> Would not something like meta II, be better for that time frame. :)
> I still find it hard that we have yet to a common meta language for computer 
> operations. Every computer just has to be different.
> Addressing modes have been the same since the 1950's.

Addressing modes barely existed in the 1950s.  The PDP11 introduced a bunch of 
new ones in 1970; the VAX a bunch more in 1978.  "Since 1978" may be true, or 
at least closer.

Some addressing modes went away, like the self-modifying "C" address mode of 
the Electrologica X1 -- http://helloworldcollection.de/#Assembler%C2%A0(X1) .  
Good riddance, actually, but it certainly was "interesting".

On a common metalanguage, there was an attempt to define such a thing, to allow 
software to be encoded in a way that could still be understood centuries from 
now.  I have a paper about it somewhere but my search attempts are failing on 
me.  I vaguely remember "Rosetta" is part of the name of the paper, but that 
just gives me lots of false matches.

paul

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

2023-01-17 Thread Wayne S via cctalk

A take (mine) on the backup/archiving problem is that any medium that is used 
for this purpose will eventually be rendered obsolete and possibly unusable 
without going to extreme measures. My solution is to use whatever (economical) 
hard disk device has the most capacity and store stuff there along with some 
metadata where possible for about 6 years and then upgrade to something new. In 
this case, because hard disk capacity is still growing, replacing 1 TB disks 
with 4 Tb in a triple mirror raid. I use a synology 4 disk bay with 4 tb disks 
that is configured as 4 mirrors. In 6 years or so i’ll upgrade to something 
like that that’s newer with bigger drives like 8 - 12 TB (might be bigger, but 
depends upon cost) . This is the best solution, both affordable and redundant 
that i currently can come up with.
I think computers will continue to use disks( and thus be supported) for the 
rest of my lifetime so I’m reasonably happy.

Sent from my iPhone

> On Jan 17, 2023, at 08:57, Chris via cctalk  wrote:
> 
>  The bottom line is you have to dispense with the fantasy that any media 
> will reliably keep data for really any length of time. You must habe 
> resundancy. You could go the optical route, but even witj redundancy I don't 
> recommend it. If it's a small amount of data, maybe it's not such a bad idea, 
> you can have 3 or more copies. But backing up a lot of stuff will be very 
> laborious. And likely won't save money as compared to magnetic disks.
> 
> I'm done with the sargasso sea of cables. I bought 2 3tb 2.5" usb drives (and 
> all my data may be bigger then 4tb). I'm scaling down everything.

[cctalk] Re: AI applied to vintage interests

I disagree. There are educated guesses. Wild guesses. And good guesses.

Chuck, don't know how learned you are in antiquities. But what would be your 
answer to the question of a word that's synonymous with "teacher", but in 
actualitu it's origin was the name of a literary character from 2500 years ago. 
It may or may not help to mention it's from Homer's Odyssey. If you sidn't 
outright know the amswer, could you make a good guess? Would you take a wild 
guess? There is in actuality a data set, as in english there are a dinite 
number of synonyms for teacher. But a person may not be aware of all the 
possibilities, so that becomes irrelevant.

It seems at this point that AI can only look shit up. I don't doubt that 
eventually these things will learn how to reason to whatever degree. But this 
point won't be reached until the damned things can make food guesses. But so 
much bullshit is being programmed into these things already, in the ways they 
are taught how to think, I really have to believe we're all going to need 
bunkers before long.

 On Tuesday, January 17, 2023, 11:56:46 AM EST, Chuck Guzis via cctalk 
 wrote:  

 On 1/16/23 22:23, Chris via cctalk wrote:
>  But which of those constitutes guessing? The computer would likely have 
>beaten me to the answer by at least a second :). It's easy enough to look up, 
>for a computer that is. But in that instance a computer wouldn't need to 
>guess. And for me, there were no multiple choices. It was hardly an educated 
>guess - I never read the friggin book as I was supposed to! (the Odyssey). But 
>the answer was a word I was familiar with from childhood, never actually 
>knowing what it's origin was (mentor).
>
"Guessing" is nothing more than an estimate of the likely answer based
on an incomplete dataset.   If you had, for example, no dataset at all,
"Blueberries" would be as good a guess as any to every question.

--Chuck

[cctalk] Re: AI applied to vintage interests

2023-01-17 Thread ben via cctalk


On 2023-01-16 10:45 p.m., Fred Cisin via cctalk wrote:

On 1/16/23 19:42, Sellam Abraham via cctalk wrote:

It didn't fall for your trick question.



On Mon, 16 Jan 2023, Chuck Guzis via cctalk wrote:

In fact, feed it the object code for a reasonably compatible
architecture and ask it to perform translation to another architecture's
object code.

Certainly within the range of human capability.



How well does it do on something "simple", and less esoteric, such as 
translating FORTRAN to BASIC?




Would not something like meta II, be better for that time frame. :)
I still find it hard that we have yet to a common meta language for 
computer operations. Every computer just has to be different.

Addressing modes have been the same since the 1950's.

And it seems everybody that used a IBM 360, always defined a new 
portable virtual machine for what ever new language the were developing. 
Then it was NEVER seen again.


It seems like until the mid 1970's it was hard to find a computer
that had real general purpose registers and lots of ram. Direct and 
indirect was the only things you got before then and drum memory.


I am playing with META II, that is really primitive, but fit the
concept of one word size and and direct/indirect addressing.

Ben.

[cctalk] Re: AI applied to vintage interests

On 1/16/23 22:20, Fred Cisin via cctalk wrote:
>
> Yes, conversion of FORTRAN-IV to Fortran-77 should be easy.
> And considering that many systems ADD capoabilities, converting
> Fortran-77 to FORTRAN-IV might be a bit harder.
>
If the FORTRAN IV program conformed to the ANSI 66 specification, no
conversion should be needed.   Certain F66 features may have been
deprecated, but they would still compile correctly on F77.

No, try a vendor-specific FORTRAN II, say, 7090 FORTRAN with all of its
"interesting" additions, just as Column 1 punches for complex and
boolean arithmetic.

Better yet, convert it to, say, F90.

--Chuck

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

 The bottom line is you have to dispense with the fantasy that any media will 
reliably keep data for really any length of time. You must habe resundancy. You 
could go the optical route, but even witj redundancy I don't recommend it. If 
it's a small amount of data, maybe it's not such a bad idea, you can have 3 or 
more copies. But backing up a lot of stuff will be very laborious. And likely 
won't save money as compared to magnetic disks.

I'm done with the sargasso sea of cables. I bought 2 3tb 2.5" usb drives (and 
all my data may be bigger then 4tb). I'm scaling down everything.

[cctalk] Re: AI applied to vintage interests

On 1/16/23 22:23, Chris via cctalk wrote:
>  But which of those constitutes guessing? The computer would likely have 
> beaten me to the answer by at least a second :). It's easy enough to look up, 
> for a computer that is. But in that instance a computer wouldn't need to 
> guess. And for me, there were no multiple choices. It was hardly an educated 
> guess - I never read the friggin book as I was supposed to! (the Odyssey). 
> But the answer was a word I was familiar with from childhood, never actually 
> knowing what it's origin was (mentor).
>
"Guessing" is nothing more than an estimate of the likely answer based
on an incomplete dataset.   If you had, for example, no dataset at all,
"Blueberries" would be as good a guess as any to every question.

--Chuck

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

> On Jan 17, 2023, at 11:26 AM, Chris via cctalk  wrote:
> 
> Why wouldbyou need a whole server? Several 2.5" usb hard drives is all you 
> meed.

But then you're dealing with stored media, and their shelf life.  USB hard 
drives may be ok so long as USB interfaces are available; if they are USB SSDs 
that's a different matter entirely.  Those would not be good for a decade on 
the shelf.

One advantage of setting up a server is that it's more obvious that something 
has failed.  If a disk on the shelf goes bad, you may not discover it for 
years, and by then the recovery may be quite hard.

paul

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

2023-01-17 Thread John Foust via cctalk

At 08:54 AM 1/17/2023, Paul Koning via cctalk wrote:
> To pick one example, I have an 1990s era Dell laptop that no longer passes 
> POST (it gives a "beep code" failure that I haven't been able to cure).  I 
> would like to get whatever is on its hard disk, but that has a proprietary 
> interface as far as I can tell and I have nothing to plug it into.

Really?  Maybe there's an odd Dell cable that goes from IDE to the mobo,
but I would be surprised if it was a proprietary drive.

- John

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

> On Jan 17, 2023, at 10:58 AM, Kenneth Gober via cctalk 
>  wrote:
> 
> ...
> There is another significant advantage to focusing on a backup strategy as
> opposed to an archival strategy -- I don't need to worry about tapes I made
> today being readable decades in the future (i.e. I don't need to worry
> about keeping legacy tape drives running).  The file server is the
> "archive" and I only *need* to be able to read the tapes I made last year
> or last month.  If a tape drive fails I can just get another one, and if
> they become hard to get there's nothing stopping me from upgrading to
> something newer with better availability (i.e. I don't have a library of
> old media that I need to be able to read forever).  The disadvantage of
> course is that a file server isn't something you can reasonably put in
> storage for future generations to access.  This strategy really only works
> if the file server is accessed frequently so that
> accessibility/compatibility issues can be fixed incrementally as they
> happen (while they are still easily addressed using current/recent
> technology).
> 
> -ken

Nice idea and a very good point.  You have to deal with a number of 
compatibility issues but they are all short range.  The backups is one aspect.  
Another is the file server protocol.  If your server uses NFS V2, some hosts 
can use it but others may not.  And the hardware on which it runs might fail.  
For these last two cases you'd have to stand up a newer file server, and in the 
case of server failure you'd have to be able to load the new server with the 
old data.  Depending on the backup media that might be problematic.  I suppose 
for both of those issues the answer is to bring up newer file servers ahead of 
time, as they become available.

You still have to deal with the question of how old format documents would be 
read.  If the formats are proprietary and no longer supported that's a problem. 
 For example, I have some old Eagle CAD files that are no longer readable.  And 
some old CorelDraw files that are also difficult, though I think I can still 
get there via intermediate old versions of the software on a VM.  And I have an 
old CPLD designed in Abel HDL; if that ever needs modification I'm going to be 
in trouble.

paul

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

 Why wouldbyou need a whole server? Several 2.5" usb hard drives is all you 
meed.

 On Tuesday, January 17, 2023, 10:59:08 AM EST, Kenneth Gober via cctalk 
 wrote:  

 On Mon, Jan 16, 2023 at 9:48 PM Fred Cisin via cctalk 
wrote:

> > What about M-DISC DVDs and BluRays?  Archival grade, not susceptible
> to magnetism or EMP.  I think BluRay discs are made of a harder material
> than DVDs and don’t scratch as easily.
>
> I have had magnetic, AND optical media that have "gone bad".
>
> I am interested in whatever media are more likely to still be readable in
> a few decades.
>

LTO tape, properly stored, is advertised as having a 30 year lifetime.  Of
course tape isn't particularly convenient for ad-hoc access so my archival
strategy is to dump things to a file server with a *lot* of disk space
(RAID1 or RAID10, not RAID0 or RAID4/RAID5), then regularly back up that
server to LTO tape.  The current generation (LTO8) is very expensive so I
use LTO4 and LTO6 tapes which are comparatively very affordable.  The data
doesn't tend to change but taking repeated backups anyway helps to ensure
that silent bit-rot on the hard disks is detected early enough to be
correctible.  Having backups on tape also has the advantage that the tapes
are easily moved off-site, so a fire or other such disaster won't take out
my server and my backups both at once.

There is another significant advantage to focusing on a backup strategy as
opposed to an archival strategy -- I don't need to worry about tapes I made
today being readable decades in the future (i.e. I don't need to worry
about keeping legacy tape drives running).  The file server is the
"archive" and I only *need* to be able to read the tapes I made last year
or last month.  If a tape drive fails I can just get another one, and if
they become hard to get there's nothing stopping me from upgrading to
something newer with better availability (i.e. I don't have a library of
old media that I need to be able to read forever).  The disadvantage of
course is that a file server isn't something you can reasonably put in
storage for future generations to access.  This strategy really only works
if the file server is accessed frequently so that
accessibility/compatibility issues can be fixed incrementally as they
happen (while they are still easily addressed using current/recent
technology).

-ken

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

2023-01-17 Thread Kenneth Gober via cctalk

On Mon, Jan 16, 2023 at 9:48 PM Fred Cisin via cctalk 
wrote:

> > What about M-DISC DVDs and BluRays?  Archival grade, not susceptible
> to magnetism or EMP.  I think BluRay discs are made of a harder material
> than DVDs and don’t scratch as easily.
>
> I have had magnetic, AND optical media that have "gone bad".
>
> I am interested in whatever media are more likely to still be readable in
> a few decades.
>

LTO tape, properly stored, is advertised as having a 30 year lifetime.  Of
course tape isn't particularly convenient for ad-hoc access so my archival
strategy is to dump things to a file server with a *lot* of disk space
(RAID1 or RAID10, not RAID0 or RAID4/RAID5), then regularly back up that
server to LTO tape.  The current generation (LTO8) is very expensive so I
use LTO4 and LTO6 tapes which are comparatively very affordable.  The data
doesn't tend to change but taking repeated backups anyway helps to ensure
that silent bit-rot on the hard disks is detected early enough to be
correctible.  Having backups on tape also has the advantage that the tapes
are easily moved off-site, so a fire or other such disaster won't take out
my server and my backups both at once.

There is another significant advantage to focusing on a backup strategy as
opposed to an archival strategy -- I don't need to worry about tapes I made
today being readable decades in the future (i.e. I don't need to worry
about keeping legacy tape drives running).  The file server is the
"archive" and I only *need* to be able to read the tapes I made last year
or last month.  If a tape drive fails I can just get another one, and if
they become hard to get there's nothing stopping me from upgrading to
something newer with better availability (i.e. I don't have a library of
old media that I need to be able to read forever).  The disadvantage of
course is that a file server isn't something you can reasonably put in
storage for future generations to access.  This strategy really only works
if the file server is accessed frequently so that
accessibility/compatibility issues can be fixed incrementally as they
happen (while they are still easily addressed using current/recent
technology).

-ken

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

2023-01-17 Thread boB via cctalk





On 1/17/2023 7:54 AM, Paul Koning via cctalk wrote:



On Jan 16, 2023, at 9:48 PM, Fred Cisin via cctalk  
wrote:


What about M-DISC DVDs and BluRays?  Archival grade, not susceptible

to magnetism or EMP.  I think BluRay discs are made of a harder material than 
DVDs and don’t scratch as easily.

On Tue, 17 Jan 2023, Chris via cctalk wrote:

Don't know, don't care. If we're being attacked by nuclear bombs of any stripe, 
I have far more humongous things to worry about then what's on my hard drives. 
I suppose if you were wring a book and wanted to back that up to an optical 
disk, go for it.

I care, and would like to know more.
Even without nuclear bombs, which I stopped worrying about 60 years ago, I have 
occasionally had to deal with damaged data, from causes much more mundane than 
EMPs.

I have had magnetic, AND optical media that have "gone bad".

I am interested in whatever media are more likely to still be readable in a few 
decades.

Not SSD, that's for sure.  The fact those are becoming the predominant storage 
medium is a bit of a concern for long term storage, because SSD is entirely 
unfit for that job.  Apparently they are ok when powered because the firmware 
will refresh the bits from time to time, but you can't put an SSD on the shelf 
and still expect its data to be good a decade later, as you can with hard 
drives.

With hard drives you have to worry about mechanical faults, of course.  I 
wonder if there are any long term storage issues with the bearings.


My understanding is that it is a good idea to plug the hard drives in 
once in a while just to get them rotating for a moment to keep the 
bearings lubricated or whatever.


So far, so good on all my backups but I am a bit bad about doing that.  
I use 2 backups at least but some of the more important stuff I use 3.


There used to be a program that would read the disk and write the bits 
back to freshen up their magnetic domains.


That might have been "Spinwriter" ?

boB




Most likely, the biggest issue with old storage devices is the loss of the device to 
connect them to, and/or the loss of the code that reads them.  To pick one example, I 
have an 1990s era Dell laptop that no longer passes POST (it gives a "beep 
code" failure that I haven't been able to cure).  I would like to get whatever is on 
its hard disk, but that has a proprietary interface as far as I can tell and I have 
nothing to plug it into.

I have an RM03 pack somewhere.  There probably are a few places left that could 
read it.  If it were an RA60 pack it would be a whole lot more problematic, I 
suspect.  Without an old drive, how would you recover the data?  Spin table?  
Perhaps, if you can find, or reverse engineer, the format.

The Long Now foundation has done work on the question of storing data in a way that can 
still be deciphered a millennium from now.  It's not a simple question.  Some SF writers 
have wrapped stories around the question (James P. Hogan did it several times -- Echoes 
of an Alien Sky, Inherit the Stars, and much earlier (1957) there was H. Beam Piper 
"Omnilingual").

Early storage devices are less problematic than newer ones, given the more and 
more complex coding used.  Never mind intentional encryption; just the high 
density codes with interleaving and ECC and all that would be somewhat akin to 
encryption when examined with a future archeologist.  Imagine, for example, an 
archeologist 5 centures from now trying to make sense out of a box full of SATA 
interface hard drives, full of documents in PDF, JPG, or MP4 format.

paul

[cctalk] Re: Positive Logic vs. Negative Logic Controller in DEC TU56

On Tue, Jan 17, 2023 at 8:39 AM Bill Degnan  wrote:

> I am working to understand a TU56 in my possession that came from an
> unknown environment.  A connecting cable that came with it reads "PDP9" on
> one end so I wondered if this is actually associated with the TU56 or just
> sitting in the same box before the TU56 came to me.  I have read here:
>
> https://gunkies.org/wiki/TU56_DECtape_Transport
>
> That one can have a TU56 with a M531 or a G742 to serve as a bus
> converter.  THe M531 is for situations where one has a negative logic
> controller and the G742 is for when one has a positive logic controller.
>
> Jumping a few steps ahead, if the TU56 was attached to a PDP-9, would it
> use a G742 if one tried to attach a TU56 to it?  I feel as if the G742
> would be used if the TU56 was intended for a PDP8 and not a PDP11, right?
>
> I searched the web and will continue to research but I thought I'd ask
> experts here.  No, I don't use ChatGPT.
>
> Bill
>

First of all, here is a set of pre-restoration pics of the TU56 I am
cleaning up and trying to understand:
https://www.vintagecomputer.net/digital/TU56/index.cfm?sort=name=DESC

I found a good general description of how the negative / positive relates
to the PDP-8 and how peripherals fit into the picture.
https://homepage.cs.uiowa.edu/~dwjones/pdp8/models/

"The "negibus" or negative logic I/O bus used -3 and 0 volt logic levels in
92 ohm coaxial cable" -  a M531 would be used if attaching to a computer
with a negative bus.  A G742 indicates the computer using the TU56 had some
form of positive logic bus.
The positive I/O bus, or posibus, was a 100 ohm bus clamped between 0 and 3
volts with TTL drivers and receivers.

BUT - The cable that connects the TU56 to the external peripheral possibly
appears to convert the posibus to a negibus as well as data.  So I am
thinking the presence of a G742 does not alone indicate the computer using
the TU56.   Note the 18 connectors:
https://www.vintagecomputer.net/digital/TU56/TU56_PDP9-connector.png

I think a PDP-9 and earlier PDP8's were negative logic computers, so it's
possible that this TU56 was used with a negative logic computer, the PDP-9
despite the G742, given
1)  The 18-pin bus adapter-ing on the other end of the TU56 positive bus
2)  THe "PDP9" printed on the adapter.
3)  The other side of the cable reads "TC02 E" (I believe).

I know PDP-9's attached to TU55's, but the TU56 was not invented yet.

TC02?
http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/DEC-00-HRTC-D%20TU56%20DECtape%20Transport%20Maintenance%20Manual.pdf
See page 22
(1) For a TU56M or TU56MH Transport: controller-to-transport information
cable = 70-06412, transport-totransport (other TU56 or TU56H in system)
information cable = 74-5152. See Note 2 for TU56M or TU56MH connected to a
TD8/e Controller. (2) When a TU56M or TU56MH is connected to a TDa TD8/e
Controller, only one 70-08447 cable is used for both commands and
information. This cable has both a single-height and a double-height
connector module on the termination end. Insert the single-height connector
into slots A061 A07 and the double-height connector into slots AB 1 01 AB I
I.

Bill

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve




> On Jan 17, 2023, at 8:58 AM, Zane Healy via cctalk  
> wrote:
> 
>> On Jan 16, 2023, at 6:48 PM, Fred Cisin via cctalk  
>> wrote:
>> 
>> I am interested in whatever media are more likely to still be readable in a 
>> few decades.
>> 
>> M-Disc claims 100 year life, but, obviously, no M-Disc has lasted that long, 
>> and they are making promises based on what they THINK will happen.
>> 
>> M-Disc BDXL is currently available in 100GB per platter.
> 
> In the early days of this list (think back 25 years), I believe it was Tim 
> Shoppa that was recommending either Gold CD-R blanks, or Verbatim 
> DataLifePlus.  If I remember correctly, he’d done some aging tests on them, 
> and they were the two that held up well.  As a result, I standardized on 
> Verbatim DataLifePlus for any CD’s I expected to be reading after a year.  
> I’ve read ones from 1997 without problem.  In fact I think I’ve only had a 
> couple minor issues.  One of the disks I read had to be washed before I could 
> even attempt it as it has been sitting out bare.
> 
> What has surprised me is the results from the floppies, mostly stored in the 
> garage for the last 15 years, and before that, I don’t remember.  Granted I 
> tended to go with higher quality floppies, but still, I’ve expected a lot 
> more issues than I’ve had.  Some of the 3.5” floppies I’ve read date back to 
> 1987 or 88.  Mind you I’ve not tried to recover data from 5.25” floppies yet, 
> I’m still trying to find those, and a big drawer/box of 3.5” floppies.

Sometimes you run into surprises with particular media manufacturers.  I 
blaclisted Fuji when 100% of my Fuji audio cassettes failed (media failing such 
that playback would be overwhelmed by squeaky noises heard on the playback, not 
just the drive mechanism).  No other brands did this sort of wholesale 
collapse, and most haven't failed at all, not even the cheaper ones.

paul

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

> On Jan 16, 2023, at 9:48 PM, Fred Cisin via cctalk  
> wrote:
> 
>> What about M-DISC DVDs and BluRays?  Archival grade, not susceptible 
> to magnetism or EMP.  I think BluRay discs are made of a harder material than 
> DVDs and don’t scratch as easily.
> 
> On Tue, 17 Jan 2023, Chris via cctalk wrote:
>> Don't know, don't care. If we're being attacked by nuclear bombs of any 
>> stripe, I have far more humongous things to worry about then what's on my 
>> hard drives. I suppose if you were wring a book and wanted to back that up 
>> to an optical disk, go for it.
> 
> I care, and would like to know more.
> Even without nuclear bombs, which I stopped worrying about 60 years ago, I 
> have occasionally had to deal with damaged data, from causes much more 
> mundane than EMPs.
> 
> I have had magnetic, AND optical media that have "gone bad".
> 
> I am interested in whatever media are more likely to still be readable in a 
> few decades.

Not SSD, that's for sure.  The fact those are becoming the predominant storage 
medium is a bit of a concern for long term storage, because SSD is entirely 
unfit for that job.  Apparently they are ok when powered because the firmware 
will refresh the bits from time to time, but you can't put an SSD on the shelf 
and still expect its data to be good a decade later, as you can with hard 
drives.

With hard drives you have to worry about mechanical faults, of course.  I 
wonder if there are any long term storage issues with the bearings.

Most likely, the biggest issue with old storage devices is the loss of the 
device to connect them to, and/or the loss of the code that reads them.  To 
pick one example, I have an 1990s era Dell laptop that no longer passes POST 
(it gives a "beep code" failure that I haven't been able to cure).  I would 
like to get whatever is on its hard disk, but that has a proprietary interface 
as far as I can tell and I have nothing to plug it into.

I have an RM03 pack somewhere.  There probably are a few places left that could 
read it.  If it were an RA60 pack it would be a whole lot more problematic, I 
suspect.  Without an old drive, how would you recover the data?  Spin table?  
Perhaps, if you can find, or reverse engineer, the format.

The Long Now foundation has done work on the question of storing data in a way 
that can still be deciphered a millennium from now.  It's not a simple 
question.  Some SF writers have wrapped stories around the question (James P. 
Hogan did it several times -- Echoes of an Alien Sky, Inherit the Stars, and 
much earlier (1957) there was H. Beam Piper "Omnilingual").

Early storage devices are less problematic than newer ones, given the more and 
more complex coding used.  Never mind intentional encryption; just the high 
density codes with interleaving and ECC and all that would be somewhat akin to 
encryption when examined with a future archeologist.  Imagine, for example, an 
archeologist 5 centures from now trying to make sense out of a box full of SATA 
interface hard drives, full of documents in PDF, JPG, or MP4 format.

paul

[cctalk] Re: [SPAM] Re: long lived media (Was: Damage to CD-R from CD Sleeve

On Jan 17, 2023, at 2:02 AM, Peter Corlett via cctalk  
wrote:
> 
> If you mean CHKDSK.EXE, it's broadly equivalent to Unix fsck plus a surface
> scan, and all fsck does is check and repair filesystem _metadata_. If the
> metadata is corrupt then that's a good sign that the data itself is also
> toast, but a successful verification of the metadata does not tell you
> anything useful about the data itself.

And this is where having Optical Discs help.  As part of my project, I’ve found 
backups from as far back as ’97, and as a result, recovered data that I’d lost 
by ’99.  That includes an update to a book that can no longer be found on the 
Internet, and all the code for a Shareware program I wrote in ’96/97.

The 3-2-1 rule says you should have at least 3 copies of your data, including 
two on different types of media, and a 3rd copy off-site.

Zane

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

> On Jan 16, 2023, at 6:48 PM, Fred Cisin via cctalk  
> wrote:
> 
> I am interested in whatever media are more likely to still be readable in a 
> few decades.
> 
> M-Disc claims 100 year life, but, obviously, no M-Disc has lasted that long, 
> and they are making promises based on what they THINK will happen.
> 
> M-Disc BDXL is currently available in 100GB per platter.

In the early days of this list (think back 25 years), I believe it was Tim 
Shoppa that was recommending either Gold CD-R blanks, or Verbatim DataLifePlus. 
 If I remember correctly, he’d done some aging tests on them, and they were the 
two that held up well.  As a result, I standardized on Verbatim DataLifePlus 
for any CD’s I expected to be reading after a year.  I’ve read ones from 1997 
without problem.  In fact I think I’ve only had a couple minor issues.  One of 
the disks I read had to be washed before I could even attempt it as it has been 
sitting out bare.

What has surprised me is the results from the floppies, mostly stored in the 
garage for the last 15 years, and before that, I don’t remember.  Granted I 
tended to go with higher quality floppies, but still, I’ve expected a lot more 
issues than I’ve had.  Some of the 3.5” floppies I’ve read date back to 1987 or 
88.  Mind you I’ve not tried to recover data from 5.25” floppies yet, I’m still 
trying to find those, and a big drawer/box of 3.5” floppies.

Zane

[cctalk] Re: Damage to CD-R from CD Sleeve

On Jan 16, 2023, at 5:11 PM, Chris via cctalk  wrote:
> 
> Been there. Seen it. It seems paper or tyvek is the way to store these things.

Thankfully most of the disks that I’ve imaged that don’t have jewel cases, are 
in paper sleeves.  Or even worse, a few have been loose.  It looks like this 
may be the main CD impacted.  It looks like most of I used these accursed 
sleeves for are DVD-R’s from nearly 20 years ago, that I don’t care about.

> But the question is in 2023 why are you still committing data to optical 
> media? I dumped all my cds and dvds on to magnetic storage years ago. I got 
> burned waiting as long as I did even.

I’m recovering CD’s and Floppies at this point, not burning, though I will 
probably see about burning these onto an M-Disc.

Zane

[cctalk] Positive Logic vs. Negative Logic Controller in DEC TU56

I am working to understand a TU56 in my possession that came from an
unknown environment.  A connecting cable that came with it reads "PDP9" on
one end so I wondered if this is actually associated with the TU56 or just
sitting in the same box before the TU56 came to me.  I have read here:

https://gunkies.org/wiki/TU56_DECtape_Transport

That one can have a TU56 with a M531 or a G742 to serve as a bus
converter.  THe M531 is for situations where one has a negative logic
controller and the G742 is for when one has a positive logic controller.

Jumping a few steps ahead, if the TU56 was attached to a PDP-9, would it
use a G742 if one tried to attach a TU56 to it?  I feel as if the G742
would be used if the TU56 was intended for a PDP8 and not a PDP11, right?

I searched the web and will continue to research but I thought I'd ask
experts here.  No, I don't use ChatGPT.

Bill

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

You have to make the best of what you have to work with needless to say. Are 
you making arguments im favor of long term optical storage? It doesn't seem so, 
but if you were, you lost me.

 On Tuesday, January 17, 2023, 05:32:33 AM EST, Peter Corlett via cctalk 
 wrote:  

 On Tue, Jan 17, 2023 at 05:42:55AM +, Chris via cctalk wrote:
[...]
> The only answer that anyone can provide is redundancy. Keep 2 or 3 copies
> of everything on seperate external drives. Every 3 to 5 years buy new
> drives and transfer the data to them. Or just run checkdisk twice a year
> and wait for 1 drive to start popping errors. Replace it. Wait for other
> to fail. Then replace it.

If you mean CHKDSK.EXE, it's broadly equivalent to Unix fsck plus a surface
scan, and all fsck does is check and repair filesystem _metadata_. If the
metadata is corrupt then that's a good sign that the data itself is also
toast, but a successful verification of the metadata does not tell you
anything useful about the data itself.

The surface scan asks the drive to read each sector, and relies on the disk
correctly identifying sectors which have changed from when they were
written. This is almost always the case, but that "< 1 in 10¹⁴" in the
datasheet is still not zero. And that's before we consider dodgy SATA cables
and buggy disk controllers. (SAS won't save you either: what it gives in
increased quality, it takes away in extra complexity.)

On typical Windows desktop computers, the probability that something else
will go wrong and destroy the system is way higher than the raw error rate
of the disk, but on non-toy systems with many tens or hundreds of terabytes
of data, the probability of a disk lying rises uncomfortably-close to 1. A
good filesystem needs to defend against disks which do that. FAT and NTFS
are not good filesystems by that measure.

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve