subject:"Re\: how good is the data reliability with CD ROM and DVD RAM\?"


On 07/24/2018 12:42 PM, Eric Smith via cctalk wrote:
I wrote a lot of DDS2 and DDS3 tapes back in the day. When my DDS3 
drive broke, I got another drive. I found out that my first drive was 
seriously out of calibration, and though it could read its own tapes, 
other drives could not. All the data was gone.


Ouch!

That sounds like a common type of problem, namely single point of 
failure on alignment.  I think I've heard of the same for floppy drives too.


I'm considering getting an LTO drive, but I won't do it unless either I 
buy two drives, or find someone else with the same generation LTO drive 
who would like to exchange encrypted backup tapes for verification.


Valid concern.

I would also like to confirm that your drive can also read tapes from 
your friend's alternate drive.


I'd really prefer if it was a trio of drives.  But that's even more 
expensive / unlikely / difficult to achieve goal.




--
Grant. . . .
unix || die

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-24 Thread Carlo Pisani via cctalk

I have a brand new DLT drive for sale
brand new, it's SCSI, 2U

2018-07-24 20:42 GMT+02:00 Eric Smith via cctalk :
> I wrote a lot of DDS2 and DDS3 tapes back in the day. When my DDS3 drive
> broke, I got another drive. I found out that my first drive was seriously
> out of calibration, and though it could read its own tapes, other drives
> could not. All the data was gone.
>
> I'm considering getting an LTO drive, but I won't do it unless either I buy
> two drives, or find someone else with the same generation LTO drive who
> would like to exchange encrypted backup tapes for verification.

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-24 Thread Eric Smith via cctalk

I wrote a lot of DDS2 and DDS3 tapes back in the day. When my DDS3 drive
broke, I got another drive. I found out that my first drive was seriously
out of calibration, and though it could read its own tapes, other drives
could not. All the data was gone.

I'm considering getting an LTO drive, but I won't do it unless either I buy
two drives, or find someone else with the same generation LTO drive who
would like to exchange encrypted backup tapes for verification.

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-24 Thread Zane Healy via cctalk




> On Jul 24, 2018, at 10:55 AM, Grant Taylor via cctalk  
> wrote:
> 
>> On 7/21/18 9:14 AM, Carlo Pisani via cctalk wrote:
>> what is your experience?
> I personally have had reasonable success with CD-Rs.
> 
> I used Verbatim Blue CD-Rs for general storage back when I had a single 6.4 
> GB drive in '98.  I have recently read the contents of all the surviving 
> disks with no problems that weren't resolved by a damp washcloth gently 
> wiping the underside of the disk.
> 
> I do seem to recall I had one disk that failed within a few months from what 
> seemed to be fungus or rot.  I never knew.  I got rid of it quickly.
> 
> All the other disks that I burned at 1x have lasted the better part of 20 
> years.
> 
> Honestly, I have more concern about functional CD-ROM drives more so than I 
> do the media.  More and more machines I'm around don't actually have a drive 
> capable of reading CD-ROMs.
> 
> I was also exposed to some people using the El-Cheapo light (faint) green 
> CD-Rs and they would end up having problems reliably reading from them a week 
> or two later.  I think they usually burned them as fast as their drive would 
> allow.  To me, old AOL floppy disks were more reliable than the light green 
> CD-Rs burned at high speed.
> 
> I would only tolerate light green burned at 1x if I needed to move bulk data 
> between machines and networking was not an option.  Once the data was there, 
> I considered the CD-R to be dead and frequently physically destroyed it.
> 
> 
> 
> -- 
> Grant. . . .
> unix || die
> 


For me, the Verbatim DataLifePlus has always been the disks that I trust.  
Though at this point I should review what is on them and move the data to 
online archives if I care about it.  Realistically a lot is old backups.  So 
far I’ve never had a problem with them, except bad burns on a flaky drive or 
system.

I have used cheap blanks for Linux installs, or to give someone copies of my 
photos.

Zane

Re: how good is the data reliability with CD ROM and DVD RAM?


On 7/21/18 9:14 AM, Carlo Pisani via cctalk wrote:

what is your experience?

I personally have had reasonable success with CD-Rs.

I used Verbatim Blue CD-Rs for general storage back when I had a single 
6.4 GB drive in '98.  I have recently read the contents of all the 
surviving disks with no problems that weren't resolved by a damp 
washcloth gently wiping the underside of the disk.


I do seem to recall I had one disk that failed within a few months from 
what seemed to be fungus or rot.  I never knew.  I got rid of it quickly.


All the other disks that I burned at 1x have lasted the better part of 
20 years.


Honestly, I have more concern about functional CD-ROM drives more so 
than I do the media.  More and more machines I'm around don't actually 
have a drive capable of reading CD-ROMs.


I was also exposed to some people using the El-Cheapo light (faint) 
green CD-Rs and they would end up having problems reliably reading from 
them a week or two later.  I think they usually burned them as fast as 
their drive would allow.  To me, old AOL floppy disks were more reliable 
than the light green CD-Rs burned at high speed.


I would only tolerate light green burned at 1x if I needed to move bulk 
data between machines and networking was not an option.  Once the data 
was there, I considered the CD-R to be dead and frequently physically 
destroyed it.




--
Grant. . . .
unix || die

Re: how good is the data reliability with CD ROM and DVD RAM?


On 7/23/18 9:51 AM, Alexander Schreiber via cctalk wrote:
Another thing to keep in mind: it is nice if your backup medium lasts 
decades, but what about the reader for it? Will that be available 
down the road as well and usable?


I seem to recall reading about a ""tape drive that wrote optically to 
the medium in such a way that it could be read optically without overly 
complex magnification.  I want to say something between a good 
magnifying glass and a cheap microscope allowed people with nominally 
20/20 vision to be able to read the bits on the tape.


The tape also purportedly had a leader that was direction on how to read 
the tape manually (optically).


The idea was that it was possible (all be it tedious) for a human to 
read the tape and gain access to the contents there in.


And, not to forget: what format are your backups written in. Something 
standard like POSIX tar or some proprietary format used by some 
commercial software, which might have availability issues in the 
future.


Yep.

I've read a few discussions where some of the oldest and biggest formats 
that take up the most space are the most likely to be recovered.  ASCII 
text being one of the most likely.


If you do use a less open / more proprietary format make sure to be 
mindful of what sort of blocking / chunking that it does.  The idea 
being that you don't want corruption somewhere in the tape to render the 
rest of the tape inaccessible.


This also nods towards redundancy.  Having multiple copies of the same 
data different places on the tape and / or on multiple tapes makes it 
much more likely that if (read: when) corruption occurs, you don't 
actually have data loss because ideally redundant copies are good.  Or 
at least between all of the copies you have at least one good aggregate 
copy of the data.




--
Grant. . . .
unix || die

Re: how good is the data reliability with CD ROM and DVD RAM?


On 7/22/18 2:06 PM, Zane Healy via cctalk wrote:
I wouldn’t touch 4mm DAT tapes with a ten foot pole, if I can help 
it.  I’ve used them in the past, but only in special cases, OR more 
importantly when forced to.


I had reasonable success with DDS2 & DDS3 DATs back in the day.  I 
routinely wrote to and read from the tapes over about 18 months.  Though 
I have no idea how well they would last longer term than that.


QIC-80 drives were really before me, but I did manage to pick some up 
from garage sales and read their contents 5+ years after they were 
written.  I usually had to retention the tapes one (or more) time(s) to 
be able to get a (few) good reads off of them.  I do think they earned 
their reputation that I've heard others talk about.


That being said, CuriousMark is having decent luck with QIC cartridges 
in his old HP equipment.


You can’t buy new LTO2 or DLT drives (I think the last DLT drives 
were DLT8000’s).  Even Super-DLT tapes are obsolete.


I've got no personal experience with DLT.  I have multiple colleagues 
that used them to backup multiple servers (before I entered the scene).


At this point, for tape, I recommend LTO8, and if this is for 
Archival purposes, you’ll need to refresh to LTO9 when released. 
LTO8 introduces an evil little gotcha.  While previous versions of 
the drives, have been able to read two versions back, LTO8 can’t.


All of my professional experience with tape has been decidedly 
non-archival.  It was always used for nightly / weekly / monthly backups 
and consumed within 18 months.


I’ve failed to see any reason behind your questions.  If you’re 
looking for a long-term archival solution, look to cloud storage 
(either on-prem, or off-prem).  Sure tape is cheap, but when you 
start looking at other costs, such as storage and handling, it 
becomes expensive.


I think you need to be EXTREMELY careful when selecting cloud storage 
vendors.  I've heard about a fewer smaller ones folding up shop.  I want 
to say I've heard of at least one going away fast enough that people had 
problems getting their data back.  So, make sure you pick one that is 
reputable and / or guarantees time to retrieve data that you have stored 
with them.


This touches on one of my personal projects this year.  I virtualized 
my backup infrastructure for my OpenVMS systems, and then I went a 
step further, and have virtualized most of my OpenVMS environment.  I 
still need to virtualize my DECnet area router.  While all the data 
is moved, I’m still working to move some apps.  It makes protecting 
my data easy.  My primary interest is the OS and software, while in 
the past I’ve been focused on running on real hardware, 
virtualization is looking real nice, even for working systems where I 
have plenty of spares.


I would love to know more about how you did this.  Do you have any blog 
articles or the likes that I can read to learn?




--
Grant. . . .
unix || die

Re: how good is the data reliability with CD ROM and DVD RAM?


On 7/23/18 12:00 PM, Geoffrey Oltmans via cctalk wrote:
Probably a good idea to use something like RAR with parity. I know I 
have downloaded some multi-segment binaries in RAR format from usenet 
with several missing segments and as long as I had the parity file 
set it could successfully recover the entire archive.
I too have had good luck with RAR files and their (optional) accompany 
PAR files.  The key word being "optional" as in not there by default.


I think some other archive formats also have (optional) built in redundancy.

I've also heard some noise that some archive file formats are 
particularly susceptible to corruption and can't be recovered.  So I do 
think it's very important to carefully pick the archive format and options.




--
Grant. . . .
unix || die

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-24 Thread Carlo Pisani via cctalk

has anyone ever used Iomega Rev as backup media?
how good is that?



2018-07-23 23:11 GMT+02:00 Ali via cctalk :
>> Probably a good idea to use something like RAR with parity. I know I
>> have
>> downloaded some multi-segment binaries in RAR format from usenet  with
>> several missing segments and as long as I had the parity file set it
>> could
>> successfully recover the entire archive.
>
> Parity will only take you so far. It is the same as RAID - you can only 
> tolerate so many disk failures before the whole thing collapses like a house 
> of cards. It works well w/ UseNet because usually the errors are small 
> compared to the data set. However, if you were missing say three RAR files 
> out of six then one PAR file is not going to save you.
>
> -Ali
>

RE: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Ali via cctalk

> Probably a good idea to use something like RAR with parity. I know I
> have
> downloaded some multi-segment binaries in RAR format from usenet  with
> several missing segments and as long as I had the parity file set it
> could
> successfully recover the entire archive.

Parity will only take you so far. It is the same as RAID - you can only 
tolerate so many disk failures before the whole thing collapses like a house of 
cards. It works well w/ UseNet because usually the errors are small compared to 
the data set. However, if you were missing say three RAR files out of six then 
one PAR file is not going to save you.

-Ali

RE: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Fred Cisin via cctalk


Does anybody here have experience with "M-Disc"?
It is available up to 100GB BDXL!
Drives start at less than $100; media is prices vary - the 100GB starts
at about $20 each, but the low capacity versions are bordering on
competitive.


On Mon, 23 Jul 2018, Ali wrote:

I have used M-Disc to archive photos and digital media. So far so good.
Problem is you need an M-Disc drive to read it for sure - what does that
mean? Well the disc is supposed to be compatible across all DVD readers BUT
I have found my older Lite-On IDE drives, which were considered very good
back in the day, have had problems reading the DVDs. So your mileage may
vary...


Thank you.

OK, that is alarming.  The claim that the discs produced are fully 
compatible is bogus.  That was an essential requirement.  Next aspect 
would be whether they are completely incompatible with EVERYTHING other 
than M-Disc, or just SOME types of drives, and if so, WHICH ones.


From what I've read, the difference in drive between BDXL and BDXL M-Disc 
is trivial enough that there is no reason that ALL BDXL wouldn't go that 
way, unless there are patent issues.




Also of note the original company has gone bankrupt and their assets bought
out. The new owners are continuing to produce M-Disc media.


The drives are being made by LG, Pioneer, etc., so that part is OK.
The media is being manufactured by Verbatim, Memorex, ?
Does the demise of the original company, and hence the licenses, place the 
ability of Verbatim, Memorex, etc. to make the media at risk?

(or only the legal rights to use the logo?)
Is the new owner more stable, and/or did Verbatim, Memorex, et al, at 
least negotiate contract provisions for continuation of license after 
demise of licensors?



Is anybody else doing any significant work towards long-life media?
We need ongoing supply, continuation of compatable hardware, and adequate 
(non-"trade-secret") documentation - without Belafon, we've lost the 
knowledge, and have to speculate, exactly what his hardware does.


--
Grumpy Ol' Fred ci...@xenosoft.com

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Zane Healy via cctalk

> On Jul 23, 2018, at 1:20 PM, Carlo Pisani via cctalk  
> wrote:
> 
> what about DVD-RAM?
> are they good about data-reliability?
> 
> cost:
> - SCSI DVD-RAM reader/writer, say about 180-240 euro, brand new
> - DVD-RAM cartridge (disk + caddy), say about 20 euro per 5 disks, brand new
> 
> how long does a DVD-RAM last?
> 
> 4.5Gbyte per disk is ok for me, I need to archive my source code

I realize this is the CLASSICCMP mail list, however, when talking about 
archiving data today, why would you use classic tech, rather than modern tech?

If you’re looking at a SCSI DVD-RAM drive, I don’t care that it’s “new”, I 
start to wonder, just how *OLD* it is.  Sure it might be “New Old Stock (NOS)", 
but it might also be “Dead on Arrival (DOA)”.

If you are trying to archive data on “Classic” hardware, if it has SCSI, then 
it surely has network, and the ability to move your data to modern hardware.

Zane

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Carlo Pisani via cctalk

what about DVD-RAM?
are they good about data-reliability?

cost:
- SCSI DVD-RAM reader/writer, say about 180-240 euro, brand new
- DVD-RAM cartridge (disk + caddy), say about 20 euro per 5 disks, brand new

how long does a DVD-RAM last?

4.5Gbyte per disk is ok for me, I need to archive my source code

2018-07-23 21:57 GMT+02:00 TeoZ via cctalk :
> What kind of media is it DVD+R or DVD-R?  I think DVD-R (Pioneer) came first
> and all the original DVD burners support it and it is the most reliable if
> you are making movies for older DVD players. DVD+R is a Sony and Phillips
> design and the recording format is different.
>
> The last generation of DVD recorders is +/- but anything IDE would probably
> be DVD-R only and might have issues reading + disks.
>
> -Original Message- From: Ali via cctalk
> Sent: Monday, July 23, 2018 2:55 PM
> To: 'Fred Cisin' ; 'General Discussion: On-Topic and Off-Topic Posts'
> Subject: RE: how good is the data reliability with CD ROM and DVD RAM?
>
>
>> Does anybody here have experience with "M-Disc"?
>>
>> It is available up to 100GB BDXL!
>> Drives start at less than $100; media is prices vary - the 100GB starts
>> at
>> about $20 each, but the low capacity versions are bordering on
>> competitive.
>
>
> Fred,
>
> I have used M-Disc to archive photos and digital media. So far so good.
> Problem is you need an M-Disc drive to read it for sure - what does that
> mean? Well the disc is supposed to be compatible across all DVD readers BUT
> I have found my older Lite-On IDE drives, which were considered very good
> back in the day, have had problems reading the DVDs. So your mileage may
> vary...
>
> Also of note the original company has gone bankrupt and their assets bought
> out. The new owners are continuing to produce M-Disc media.
>
> -Ali
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread TeoZ via cctalk

What kind of media is it DVD+R or DVD-R?  I think DVD-R (Pioneer) came first 
and all the original DVD burners support it and it is the most reliable if 
you are making movies for older DVD players. DVD+R is a Sony and Phillips 
design and the recording format is different.


The last generation of DVD recorders is +/- but anything IDE would probably 
be DVD-R only and might have issues reading + disks.


-Original Message- 
From: Ali via cctalk

Sent: Monday, July 23, 2018 2:55 PM
To: 'Fred Cisin' ; 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: how good is the data reliability with CD ROM and DVD RAM?


Does anybody here have experience with "M-Disc"?

It is available up to 100GB BDXL!
Drives start at less than $100; media is prices vary - the 100GB starts
at
about $20 each, but the low capacity versions are bordering on
competitive.


Fred,

I have used M-Disc to archive photos and digital media. So far so good.
Problem is you need an M-Disc drive to read it for sure - what does that
mean? Well the disc is supposed to be compatible across all DVD readers BUT
I have found my older Lite-On IDE drives, which were considered very good
back in the day, have had problems reading the DVDs. So your mileage may
vary...

Also of note the original company has gone bankrupt and their assets bought
out. The new owners are continuing to produce M-Disc media.

-Ali 



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Eric Smith via cctalk

On Mon, Jul 23, 2018 at 11:48 AM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> I think that the use of tapes in the 23rd century justifies their
> reputation for durability:
>
> http://memory-alpha.wikia.com/wiki/Microtape

Very impressive, since Microtape was first sold in 1963, as an enhancement
over the previous LINCtape (ca. 1961).

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread allison via cctalk

On 07/23/2018 09:21 AM, Devin Monnens via cctech wrote:
>> I have a lot of backup here stored in CDs, and I have recently bought
>> an SCSI DVDRAM unit to create new backups in caddies DVD-RAMs (of
>> 4.2Gbyte each)
>
> what is your experience?
>
>
>  I recently disposed of a couple hundred DVD and CD backups I'd made. As
> mentioned in a previous comment, it's simply too impractical to store
> terabytes of information in 4.7GB segments, plus they take up a LOT of
> space. HDDs aren't the most reliable, but this is what I use now for that
> reason. I make sure to keep the previous backup in case something happens.
> I'll only use optical backups now with the most important data.
>
> Backblaze has some interesting stats regarding HDD reliability (they are a
> data center using thousands of drives running constantly):
> https://www.backblaze.com/blog/hard-drive-stats-for-q1-2018/
>
> As noted previously, beyond storage conditions, disc longevity depends on
> the types of dyes used in the discs. Gold is supposed to be best. Early on,
> they experimented with a wide variety of dye types, and the silver dyes
> were least reliable, oxidizing in only about 10 years.
>
> The thing is, no media format is going to last forever. The only really
> reliable way of keeping data around is multiple backups and data migration.
> Basically, for your really important stuff, you'll want a couple of
> backups, stored in different geographical locations (one local, one on
> cloud works, too). You'll want to periodically refresh the backups by
> migrating the data onto fresh media.
>
> In the preservation business, the ideal is to refresh after the cost of
> storage media is 1/2 of the initial investment. So, if you paid $1 a GB for
> the initial storage media, you'll want to migrate once the new format is
> $0.50 a GB, and then again when it is $0.25 and so on. This way, the total
> cost is double what you initially invested.
>
> Of course, while the cost per GB might drop steadily, the total amount on a
> particular media format will increase as well, such that the $150 HDD you
> bought 5 years ago will have twice the storage for...$150. Definitely open
> to other suggestions.

I remember the first video disks that after 10 years would develop
sparklies
(video noise from errors).

I rarely use optical disks of any for though I still have CDR as a small
but
locally handy media.  There are many others over the years.  I generally
keep a few formats as working copies.  Any media for that gets refreshed
as needed and master copies are abundant as a backup.  Its rare they all
fail
at the same time, least I've never seen that.

For example for the CP/M systems 8", 5,25, and 3.5" floppies, refreshed
every so often.
The exception is the hard sector 5.25 stuff.  The pdp11 has RX01/2 and RX33
Both PDP11 and uVAX I have a large number of RD52 (Quantum D540s 31mb)
I use as cold swap backup storage media.  They are very good as the
media is
plated nickel-cobalt not the usual brown rust.  With more than two
decades of
doing that none have thrown an error or failed.  Of the larger RZ56s are
basically
used the same way save for SCSI class.

For the PC, I use older PC with big disks.  They are air-gapped
backups.  There are
several with all the same stuff in case one fails.  The routine is to
install and run
a new data drive for a while then copy the smaller to it and archive the
smaller.
Over the last few years I've resorted to using  large disks in a USB
case (so called
backup drives) where the case is open-able and I swap drive into them as
archive
copies with a write, verify, remove, and store cycle.  Big drives 300GB
to 1TB are
dirt cheap and I use them like flash sticks. 

 I also use USB flash as they seem solid though somewhat small if you
don't re-write
a lot.   I have a few that are a mere 128K byte that are over a decade
old and still
going.  However I am wary of widows systems as they tend to write a lot
of crap
on them besides the actual file.  Linux is kinder to them.

Allison

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Devin Monnens via cctalk

>
> I have a lot of backup here stored in CDs, and I have recently bought
> an SCSI DVDRAM unit to create new backups in caddies DVD-RAMs (of
> 4.2Gbyte each)


what is your experience?


 I recently disposed of a couple hundred DVD and CD backups I'd made. As
mentioned in a previous comment, it's simply too impractical to store
terabytes of information in 4.7GB segments, plus they take up a LOT of
space. HDDs aren't the most reliable, but this is what I use now for that
reason. I make sure to keep the previous backup in case something happens.
I'll only use optical backups now with the most important data.

Backblaze has some interesting stats regarding HDD reliability (they are a
data center using thousands of drives running constantly):
https://www.backblaze.com/blog/hard-drive-stats-for-q1-2018/

As noted previously, beyond storage conditions, disc longevity depends on
the types of dyes used in the discs. Gold is supposed to be best. Early on,
they experimented with a wide variety of dye types, and the silver dyes
were least reliable, oxidizing in only about 10 years.

The thing is, no media format is going to last forever. The only really
reliable way of keeping data around is multiple backups and data migration.
Basically, for your really important stuff, you'll want a couple of
backups, stored in different geographical locations (one local, one on
cloud works, too). You'll want to periodically refresh the backups by
migrating the data onto fresh media.

In the preservation business, the ideal is to refresh after the cost of
storage media is 1/2 of the initial investment. So, if you paid $1 a GB for
the initial storage media, you'll want to migrate once the new format is
$0.50 a GB, and then again when it is $0.25 and so on. This way, the total
cost is double what you initially invested.

Of course, while the cost per GB might drop steadily, the total amount on a
particular media format will increase as well, such that the $150 HDD you
bought 5 years ago will have twice the storage for...$150. Definitely open
to other suggestions.

RE: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Ali via cctalk

> Does anybody here have experience with "M-Disc"?
> 
> It is available up to 100GB BDXL!
> Drives start at less than $100; media is prices vary - the 100GB starts
> at
> about $20 each, but the low capacity versions are bordering on
> competitive.

Fred,

I have used M-Disc to archive photos and digital media. So far so good.
Problem is you need an M-Disc drive to read it for sure - what does that
mean? Well the disc is supposed to be compatible across all DVD readers BUT
I have found my older Lite-On IDE drives, which were considered very good
back in the day, have had problems reading the DVDs. So your mileage may
vary...

Also of note the original company has gone bankrupt and their assets bought
out. The new owners are continuing to produce M-Disc media.

-Ali

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Geoffrey Oltmans via cctalk

On Mon, Jul 23, 2018 at 12:54 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

>
> IMIHO, a grievous error by making things too physically small.  The
> standard SD card is easy enough to pick out in a deep-pile carpet.  Not
> so, the usual black-colored MicriSD.  The dog might well eat it without
> even being aware of having done it.
>
> Are there such things as "microSD" to "standard SD" adapters that allows
> for insertion of standard SD into mcroSD slots?
>

I agree. Most sold today come with a microSD to SD adapter.

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Geoffrey Oltmans via cctalk

On Sun, Jul 22, 2018 at 7:13 PM, Charles Dickman via cctalk <
cctalk@classiccmp.org> wrote:

> Below is a sampling of disks recorded between 2001 and 2009. It is
> likely that the disks of the same type were from the same package
> because I don't use many disks. They were stored without much care,
> but in a spaces tolerable to humans for reasonable periods.
>
> Imation CD-Rrecorded 2003/12/29  readable
> Imation CD-Rrecorded 2004/01/02  recoverable errors
> Imation CR-Rrecorded 2001/12/18  recoverable errors
> Imation CD-Rrecorded 2005/07/15  recoverable errors
> Imation CD-Rrecorded 2001/12/24  recoverable errors
> TDK  DVD-R recorded 2006/02/05  recoverable errors
> TDK  DVD-R recorded 2009/09   unrecoverable errors. The
> edges of the disk have a strange faded coloration.
> TDK  DVD-R recorded 2007/10/07  readable
> Memorex  CD-Rrecorded 2005unrecoverable errors
>
>
>
Probably a good idea to use something like RAR with parity. I know I have
downloaded some multi-segment binaries in RAR format from usenet  with
several missing segments and as long as I had the parity file set it could
successfully recover the entire archive.

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Chuck Guzis via cctalk

On 07/22/2018 09:05 PM, Warner Losh via cctalk wrote:
> Throughout this whole thread, I've been tempted to say that you get better
> data fidelity if you take a green magic marker and mark the edges of the
> disk...

On the other hand, information on MicroSD cards is likely to end up in
the sewer system, lost between floorboard cracks or vacuumed or swept
into the rubbish bin accidentally.

IMIHO, a grievous error by making things too physically small.  The
standard SD card is easy enough to pick out in a deep-pile carpet.  Not
so, the usual black-colored MicriSD.  The dog might well eat it without
even being aware of having done it.

Are there such things as "microSD" to "standard SD" adapters that allows
for insertion of standard SD into mcroSD slots?

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Chuck Guzis via cctalk

On 07/22/2018 09:05 PM, Warner Losh via cctalk wrote:
> Throughout this whole thread, I've been tempted to say that you get better
> data fidelity if you take a green magic marker and mark the edges of the
> disk...
> 

I think that the use of tapes in the 23rd century justifies their
reputation for durability:

http://memory-alpha.wikia.com/wiki/Microtape

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Alexander Schreiber via cctalk

On Sun, Jul 22, 2018 at 08:06:24PM +0200, Carlo Pisani via cctalk wrote:
> thus DDS4, LTO2, DLT: which is the best tape?

If you even remotely care about your data, stay far away from DDS.
In a previous job we used DDS3 tapes as system backup and restore
tapes (since the machines could boot from them). Those were written
at most once a month and in 1.5 years there I accumulated a nice stack
of 'dead' (hard read errors) tapes. I think none survived more than
half a dozen write cycles and they got read not much more.

Generally, avoiding any helical scan tape technology (DDS, AIT) is
probably a good idea on account of increased head & tape wear this
causes.

Personally, I have good experience with both DLT and LTO, both are
linear scan technologies and IIRC are specified to last at least
1-2 decades given proper storage.

Of course, you still want several generations and copies of your backups.

Another thing to keep in mind: it is nice if your backup medium lasts
decades, but what about the reader for it? Will that be available
down the road as well and usable?

And, not to forget: what format are your backups written in. Something
standard like POSIX tar or some proprietary format used by some
commercial software, which might have availability issues in the
future.

Kind regards,
Alex.

> 
> 2018-07-22 18:11 GMT+02:00 Jon Elson via cctalk :
> > On 07/22/2018 10:52 AM, Chuck Guzis via cctalk wrote:
> >>
> >> On 07/22/2018 06:33 AM, Paul Koning via cctalk wrote:
> >>>
> >>>
>  On Jul 21, 2018, at 3:25 PM, Carlo Pisani via cctalk
>   wrote:
> 
>  ...
>  and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)
> 
>  which of them lasts for the most?
> >>>
> >>> I don't know specifically.  I do know that plain old audio tapes may fail
> >>> -- I have perhaps 100 cassettes recorded in the 1970s.  Most of them are
> >>> fine, but essentially all of them that are Fuji brand have failed utterly.
> >>
> >> Half-inch open-reel tape at 1600 PE density.  Should be good for 50
> >> years at least.
> >>
> >>
> > Well, you are one of the experts in this, but it all depends on storage
> > conditions.  Also, the extended-length tapes were too thin, and suffered
> > from creasing and print-through.  Badly stored, and you can kiss your data
> > goodbye in less than 5 years.
> >
> > Jon

-- 
"Opportunity is missed by most people because it is dressed in overalls and
 looks like work."  -- Thomas A. Edison

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Jules Richardson via cctalk


On 07/21/2018 10:14 AM, Carlo Pisani via cctalk wrote:

hi
yesterday I was shocked by a couple of videos on Youtube where guys
pointed out their negative experiences with CD ROM and DVD RAM as
media for their own backup.

They complained their data completely lost after 5 years of storage in
CD ROMs, pointing out that their CDs were perfectly conserved and kept
clean without scratches, but all the data is gone lost since the media
is unreadable.


I've found in the past that problems with CDs are two-fold:

1) Deterioration of the media itself (which was particularly bad in the 
early days)


2) Incompatibilities with media and/or the burning process across drives 
and platforms.


The latter cropped up time and again, enough that I decided it was too 
risky to keep data on CD because I might want to come back to it 5 or 10 
(or more) years later and find that no hardware that I had available was 
capable of reading it.


I don't know if DVD is any better; I developed a deep mistrust of any 
optical media and so I avoid it except for transient stuff where there's no 
alternative.


cheers

Jules

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-23 Thread Peter Coghlan via cctalk

Grumpy Ol' Fred wrote:

On Sun, 22 Jul 2018, Chuck Guzis via cctalk wrote:
> I'd almost forgotten about that old chestnut.  Fortunately, Snopes
> remembers:
> https://www.snopes.com/fact-check/bewaring-of-the-green/

But, what about using a gold USB cable?

Only if it is pure gold.  None of this plated nonsense.

Surely the quality of the power filtration must make a difference.

Well, if we are talking audio, maybe there would be a hum if it is not
filtered right.

However, my one time boss once told me that he had a friend who was an
audio nut who swore the sound from his amplifier was better when he
swapped the live and neutral wires in the mains plug...

And, what about the SOURCE of the power?  Wouldn't discs be more reliable 
if the drive is driven by solar power, rather than nuclear?

Surely rotating discs have to perform better when driven by power that comes
from a rotating machine, unless someone has been stupid enough to have the
discs rotate in the opposite direction to the power generator...

Vibrations are an obvious culprit.  That can be easily proven by 
beating on drums on the table where the drive is.  The burning should be 
done in an acoustically sealed environment.

Or the drumming should be done in an oxygen free, airtight environment.
(There may be a brief period of instability at the beginning but things
should quickly settle down.)

Light leakage mmust also affect it.  All burning should be done in total 
darkness, although some claim that a #10 safelight should be OK.

If you can't see the disc turning, how can you know it has been burnt!

:-)

Regards,
Peter Coghlan.

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Fred Cisin via cctalk


On Sun, 22 Jul 2018, Chuck Guzis via cctalk wrote:

I'd almost forgotten about that old chestnut.  Fortunately, Snopes
remembers:
https://www.snopes.com/fact-check/bewaring-of-the-green/


But, what about using a gold USB cable?

Surely the quality of the power filtration must make a difference.

And, what about the SOURCE of the power?  Wouldn't discs be more reliable 
if the drive is driven by solar power, rather than nuclear?


Vibrations are an obvious culprit.  That can be easily proven by 
beating on drums on the table where the drive is.  The burning should be 
done in an acoustically sealed environment.


Light leakage mmust also affect it.  All burning should be done in total 
darkness, although some claim that a #10 safelight should be OK.


. . .

Re: how good is the data reliability with CD ROM and DVD RAM?

On 07/22/2018 09:05 PM, Warner Losh via cctalk wrote:

> Of course, I know people here will get that old, tired meme...  It got me
> wondering, though, if anybody tested that hypothesis for longevity since
> the marker would seal the edges... maybe :)

I don't know about sealing anything, as the layer of ink deposited would
likely be so thin and porous.

I'd almost forgotten about that old chestnut.  Fortunately, Snopes
remembers:

https://www.snopes.com/fact-check/bewaring-of-the-green/

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Warner Losh via cctalk

Throughout this whole thread, I've been tempted to say that you get better
data fidelity if you take a green magic marker and mark the edges of the
disk...

Of course, I know people here will get that old, tired meme...  It got me
wondering, though, if anybody tested that hypothesis for longevity since
the marker would seal the edges... maybe :)

Warner

On Sun, Jul 22, 2018 at 9:07 PM, hollandia--- via cctalk <
cctalk@classiccmp.org> wrote:

> Is there any relationship betwween the SPEED at which laser-disks are
> written and the length of time that the recording will last?
>
> Kurt
>
>
> >> On Jul 22, 2018, at 6:47 PM, Chuck Guzis via cctalk
> >>  wrote:
> >>
> >> On 07/22/2018 06:34 PM, Zane Healy via cctalk wrote:
> >>
> >>> On premises has the exact same problem as tape.  You must have a
> >>> refresh plan.  That’s the advantage of off prem, you don’t have to
> >>> worry about refresh.
> >>
> >> I don't exactly follow you.   In the case of a specific example for NASA
> >> and its vendors a given mission may involve tens of thousands of tapes.
> >> When a mission concludes, tapes are usually bundled off to a warehouse
> >> and then later junked.   There's no money in the mission budget for
> >> preservation ad perpetuum.
> >>
> >> --Chuck
>
>
>

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread hollandia--- via cctalk

Is there any relationship betwween the SPEED at which laser-disks are
written and the length of time that the recording will last?

Kurt


>> On Jul 22, 2018, at 6:47 PM, Chuck Guzis via cctalk
>>  wrote:
>>
>> On 07/22/2018 06:34 PM, Zane Healy via cctalk wrote:
>>
>>> On premises has the exact same problem as tape.  You must have a
>>> refresh plan.  Thatâs the advantage of off prem, you donât have to
>>> worry about refresh.
>>
>> I don't exactly follow you.   In the case of a specific example for NASA
>> and its vendors a given mission may involve tens of thousands of tapes.
>> When a mission concludes, tapes are usually bundled off to a warehouse
>> and then later junked.   There's no money in the mission budget for
>> preservation ad perpetuum.
>>
>> --Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Zane Healy via cctalk

> On Jul 22, 2018, at 6:47 PM, Chuck Guzis via cctalk  
> wrote:
> 
> On 07/22/2018 06:34 PM, Zane Healy via cctalk wrote:
> 
>> On premises has the exact same problem as tape.  You must have a refresh 
>> plan.  That’s the advantage of off prem, you don’t have to worry about 
>> refresh.
> 
> I don't exactly follow you.   In the case of a specific example for NASA
> and its vendors a given mission may involve tens of thousands of tapes.
> When a mission concludes, tapes are usually bundled off to a warehouse
> and then later junked.   There's no money in the mission budget for
> preservation ad perpetuum.
> 
> --Chuck

That’s the whole point of Cloud-based archives, as long as someone pays the 
“small” annual bill, the data is preserved, and someone else worries about the 
refresh of the data to more modern storage solutions.  Theoretically it’s also 
easier to find data in the cloud, but that depends on if you simply throw the 
data up there in the cloud, or if you take the time to do it right.  My guess 
is most will simply toss it up into the cloud and forget about it.  At some 
point, some bean-counter will ask why the bill has grown so large, and then…

Zane

Re: how good is the data reliability with CD ROM and DVD RAM?

On 07/22/2018 06:34 PM, Zane Healy via cctalk wrote:

> On premises has the exact same problem as tape.  You must have a refresh 
> plan.  That’s the advantage of off prem, you don’t have to worry about 
> refresh.

I don't exactly follow you.   In the case of a specific example for NASA
and its vendors a given mission may involve tens of thousands of tapes.
When a mission concludes, tapes are usually bundled off to a warehouse
and then later junked.   There's no money in the mission budget for
preservation ad perpetuum.

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Zane Healy via cctalk

> On Jul 22, 2018, at 6:08 PM, Paul Koning  wrote:
> 
>> On Jul 22, 2018, at 4:06 PM, Zane Healy via cctalk  
>> wrote:
>> 
>>> ...
>> 
>> I’ve failed to see any reason behind your questions.  If you’re looking for 
>> a long-term archival solution, look to cloud storage (either on-prem, or 
>> off-prem).  Sure tape is cheap, but when you start looking at other costs, 
>> such as storage and handling, it becomes expensive.
> 
> Cloud storage as in "handled by some cloud company" is only as good as the 
> longevity of that company.  If it shuts down suddenly because of poor 
> management or fraud, your data is almost certainly gone.  Or it might end up 
> disclosed to whoever pays pennies on the dollar for the company assets.
> 
> On premises, sure, but now it's just a question of what medium you like.  
> Those storage devices probably use disks, or maybe flash storage.  How long 
> do those last?  For example, take a look at the "power off" retention time 
> spec for flash storage, it's surprisingly short.  And how long is the 
> relevant software available?  (That's a concern for any kind of digital 
> storage, of course.)

There are only a couple cloud companies I’d recommend storing data with, for 
precisely the reasons you give.  Storing with two would be advisable.  Or a 
hybrid on and off premises approach.  For my photography archives, I’m taking a 
hybrid approach, recent changes are backed up to Drobo, everything is cloned 
and kept offsite, and then all photo’s are also sent to Cloud Storage.  Once 
you start planning for Backups as part of your storage purchases, it becomes 
easier to handle.

On premises has the exact same problem as tape.  You must have a refresh plan.  
That’s the advantage of off prem, you don’t have to worry about refresh.

For archives to be done right, you need at least two copies, excellent 
documentation, and a solid refresh plan.

Zane

Re: how good is the data reliability with CD ROM and DVD RAM?

On 07/22/2018 05:46 PM, Warner Losh via cctalk wrote:
> Somewhat of a tangent, but this just popped up for me.
> 
> https://www.theatlantic.com/technology/archive/2018/07/microfilm-lasts-half-a-millennium/565643/

I read through to the end of the article and can't quite see where the
500 year lifetime comes in.  Microfilm is a Mylar base with a gelatin
coating containing bits of elemental silver, no?   Why would this last
for 500 years?  Do we even have a 250-year old piece of intact gelatin?

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Paul Koning via cctalk

> On Jul 22, 2018, at 4:06 PM, Zane Healy via cctalk  
> wrote:
> 
>> ...
> 
> I’ve failed to see any reason behind your questions.  If you’re looking for a 
> long-term archival solution, look to cloud storage (either on-prem, or 
> off-prem).  Sure tape is cheap, but when you start looking at other costs, 
> such as storage and handling, it becomes expensive.

Cloud storage as in "handled by some cloud company" is only as good as the 
longevity of that company.  If it shuts down suddenly because of poor 
management or fraud, your data is almost certainly gone.  Or it might end up 
disclosed to whoever pays pennies on the dollar for the company assets.

On premises, sure, but now it's just a question of what medium you like.  Those 
storage devices probably use disks, or maybe flash storage.  How long do those 
last?  For example, take a look at the "power off" retention time spec for 
flash storage, it's surprisingly short.  And how long is the relevant software 
available?  (That's a concern for any kind of digital storage, of course.)

paul

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Fred Cisin via cctalk

On Sun, 22 Jul 2018, Warner Losh via cctalk wrote:

Somewhat of a tangent, but this just popped up for me.
https://www.theatlantic.com/technology/archive/2018/07/microfilm-lasts-half-a-millennium/565643/
and I thought of this thread. Apologies if it's a duplicate..

Iff deliberately processed for archival permanence, metallic silver is
long lasting.

But, there have always been a lot of shortcuts taken to save time or
money.

A LOT of photographic materials were not adequately fixed ("hypo"/Sodium
Thiosulfate?), and/or not adequately washed and or neutralizing the fixer.

Archivala permanence calls for a fixer neutralizer, not just washing.

For example, the Polaroid 55-P/N (4x5 print plus negative) had a different
exposure index for the negative and the print, so one or the other would
be off on exposure. The negative desperately needed to be more
thoroughly fixed and washed, or it didn't last at all.

Similarly with "stabilization" black and white prints. (anybody want an
extra large stabilization processor? home lab movie film processing
equipment?)

There were many variations in the paper itself for photo prints. Some
lasted better than others. Kodak has discontinued manufacturing of B
photo paper, but there are a few other manufacturers still around.

Color was done with dies, rather than metallic silver, and those fade.
Remember how OVERLY bright Kodachrome was? Ektachrome held up a bit
better.

Longevity of digital data is predicated on periodic re-copying, and
periodic transfer to other and newer media.

"Cloud" is tempting, but the internet is written in sand; do you know ehre
your data is?

--
Grumpy Ol' Fred ci...@xenosoft.com

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Paul Koning via cctalk

> On Jul 22, 2018, at 8:46 PM, Warner Losh via cctalk  
> wrote:
> 
> Somewhat of a tangent, but this just popped up for me.
> 
> https://www.theatlantic.com/technology/archive/2018/07/microfilm-lasts-half-a-millennium/565643/
> 
> and I thought of this thread. Apologies if it's a duplicate..
> 
> Warner

Interesting.  The article seems to say that it isn't the images on the film 
that last 500 years, only the substrate.  The images would last too, if done by 
silver nitrate (original black & white technology).  Later dye based stuff, 
like the blue you see on DEC microfiche, not so clear.  Probably not; I 
wouldn't trust organic dyes to last a century.

I suppose that this stuff would be discussed on the Long Now Foundation website.

paul

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Warner Losh via cctalk

Somewhat of a tangent, but this just popped up for me.

https://www.theatlantic.com/technology/archive/2018/07/microfilm-lasts-half-a-millennium/565643/

and I thought of this thread. Apologies if it's a duplicate..

Warner

On Sun, Jul 22, 2018 at 6:13 PM, Charles Dickman via cctalk <
cctalk@classiccmp.org> wrote:

> Below is a sampling of disks recorded between 2001 and 2009. It is
> likely that the disks of the same type were from the same package
> because I don't use many disks. They were stored without much care,
> but in a spaces tolerable to humans for reasonable periods.
>
> Imation CD-Rrecorded 2003/12/29  readable
> Imation CD-Rrecorded 2004/01/02  recoverable errors
> Imation CR-Rrecorded 2001/12/18  recoverable errors
> Imation CD-Rrecorded 2005/07/15  recoverable errors
> Imation CD-Rrecorded 2001/12/24  recoverable errors
> TDK  DVD-R recorded 2006/02/05  recoverable errors
> TDK  DVD-R recorded 2009/09   unrecoverable errors. The
> edges of the disk have a strange faded coloration.
> TDK  DVD-R recorded 2007/10/07  readable
> Memorex  CD-Rrecorded 2005unrecoverable errors
>
> -chuck
>

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Charles Dickman via cctalk

Below is a sampling of disks recorded between 2001 and 2009. It is
likely that the disks of the same type were from the same package
because I don't use many disks. They were stored without much care,
but in a spaces tolerable to humans for reasonable periods.

Imation CD-Rrecorded 2003/12/29  readable
Imation CD-Rrecorded 2004/01/02  recoverable errors
Imation CR-Rrecorded 2001/12/18  recoverable errors
Imation CD-Rrecorded 2005/07/15  recoverable errors
Imation CD-Rrecorded 2001/12/24  recoverable errors
TDK  DVD-R recorded 2006/02/05  recoverable errors
TDK  DVD-R recorded 2009/09   unrecoverable errors. The
edges of the disk have a strange faded coloration.
TDK  DVD-R recorded 2007/10/07  readable
Memorex  CD-Rrecorded 2005unrecoverable errors

-chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Zane Healy via cctalk

> On Jul 22, 2018, at 11:06 AM, Carlo Pisani via cctalk  
> wrote:
> 
> thus DDS4, LTO2, DLT: which is the best tape?

I wouldn’t touch 4mm DAT tapes with a ten foot pole, if I can help it.  I’ve 
used them in the past, but only in special cases, OR more importantly when 
forced to.

You can’t buy new LTO2 or DLT drives (I think the last DLT drives were 
DLT8000’s).  Even Super-DLT tapes are obsolete.  

At this point, for tape, I recommend LTO8, and if this is for Archival 
purposes, you’ll need to refresh to LTO9 when released.  LTO8 introduces an 
evil little gotcha.  While previous versions of the drives, have been able to 
read two versions back, LTO8 can’t.

I’ve failed to see any reason behind your questions.  If you’re looking for a 
long-term archival solution, look to cloud storage (either on-prem, or 
off-prem).  Sure tape is cheap, but when you start looking at other costs, such 
as storage and handling, it becomes expensive.

This touches on one of my personal projects this year.  I virtualized my backup 
infrastructure for my OpenVMS systems, and then I went a step further, and have 
virtualized most of my OpenVMS environment.  I still need to virtualize my 
DECnet area router.  While all the data is moved, I’m still working to move 
some apps.  It makes protecting my data easy.  My primary interest is the OS 
and software, while in the past I’ve been focused on running on real hardware, 
virtualization is looking real nice, even for working systems where I have 
plenty of spares.

Zane

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Carlo Pisani via cctalk

thus DDS4, LTO2, DLT: which is the best tape?

2018-07-22 18:11 GMT+02:00 Jon Elson via cctalk :
> On 07/22/2018 10:52 AM, Chuck Guzis via cctalk wrote:
>>
>> On 07/22/2018 06:33 AM, Paul Koning via cctalk wrote:
>>>
>>>
 On Jul 21, 2018, at 3:25 PM, Carlo Pisani via cctalk
  wrote:

 ...
 and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)

 which of them lasts for the most?
>>>
>>> I don't know specifically.  I do know that plain old audio tapes may fail
>>> -- I have perhaps 100 cassettes recorded in the 1970s.  Most of them are
>>> fine, but essentially all of them that are Fuji brand have failed utterly.
>>
>> Half-inch open-reel tape at 1600 PE density.  Should be good for 50
>> years at least.
>>
>>
> Well, you are one of the experts in this, but it all depends on storage
> conditions.  Also, the extended-length tapes were too thin, and suffered
> from creasing and print-through.  Badly stored, and you can kiss your data
> goodbye in less than 5 years.
>
> Jon

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Jon Elson via cctalk


On 07/22/2018 10:52 AM, Chuck Guzis via cctalk wrote:

On 07/22/2018 06:33 AM, Paul Koning via cctalk wrote:



On Jul 21, 2018, at 3:25 PM, Carlo Pisani via cctalk  
wrote:

...
and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)

which of them lasts for the most?

I don't know specifically.  I do know that plain old audio tapes may fail -- I 
have perhaps 100 cassettes recorded in the 1970s.  Most of them are fine, but 
essentially all of them that are Fuji brand have failed utterly.

Half-inch open-reel tape at 1600 PE density.  Should be good for 50
years at least.


Well, you are one of the experts in this, but it all depends 
on storage conditions.  Also, the extended-length tapes were 
too thin, and suffered from creasing and print-through.  
Badly stored, and you can kiss your data goodbye in less 
than 5 years.


Jon

Re: how good is the data reliability with CD ROM and DVD RAM?

On 07/22/2018 06:33 AM, Paul Koning via cctalk wrote:
> 
> 
>> On Jul 21, 2018, at 3:25 PM, Carlo Pisani via cctalk  
>> wrote:
>>
>> ...
>> and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)
>>
>> which of them lasts for the most?
> 
> I don't know specifically.  I do know that plain old audio tapes may fail -- 
> I have perhaps 100 cassettes recorded in the 1970s.  Most of them are fine, 
> but essentially all of them that are Fuji brand have failed utterly.

Half-inch open-reel tape at 1600 PE density.  Should be good for 50
years at least.

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread Paul Koning via cctalk

> On Jul 21, 2018, at 3:25 PM, Carlo Pisani via cctalk  
> wrote:
> 
> ...
> and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)
> 
> which of them lasts for the most?

I don't know specifically.  I do know that plain old audio tapes may fail -- I 
have perhaps 100 cassettes recorded in the 1970s.  Most of them are fine, but 
essentially all of them that are Fuji brand have failed utterly.

paul

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-22 Thread TeoZ via cctalk

The last generation 5.25" 4.x GB MO drive was unreliable which is why they 
never went bigger I think. I have a bunch of 5.25" drives from a few makers 
and all work.

-Original Message- 
From: Carlo Pisani via cctalk

Sent: Saturday, July 21, 2018 5:43 PM
To: Chuck Guzis ; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: how good is the data reliability with CD ROM and DVD RAM?

thus, MO drive units are not reliable?

2018-07-21 23:34 GMT+02:00 Chuck Guzis via cctalk :

On 07/21/2018 02:12 PM, TeoZ via cctalk wrote:

I have old IBM MO Worm disks that are still readable, same with all my
MO disks (3.5" 130MB, 5.25" 1.3GB) but drives can be iffy. I would bet
that MO media will outlast us all while finding a drive to read them
will be a problem.

I've got a few old PMC Apex 4GB disks.  I suspect that finding a working
drive will be most difficult.  Heaven knows, mine died years ago.

--Chuck

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Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-21 Thread Chuck Guzis via cctalk

On 07/21/2018 02:43 PM, Carlo Pisani wrote:
> thus, MO drive units are not reliable?

At least not the later PMC ones.  I remember that my drive wasn't even 6
months old when it died.  PMC's policy was to replace it with a
"refurbished" (read: used) replacement.  That one barely lasted a month.
 PMC then stated that their backlog on replacements was something like
12 weeks.   I wrote the cost of the drive off and moved on.  PMC ceased
operation shortly thereafter.

Mind you, I was using the drive only for testing, so fortunately no
important data was stored there.

I note that the southern California operation that bought the bankruptcy
sale stock is still in operation and offers a refurb Apex drive for
about $250 with a 30-day warranty.

No Thanks.

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-21 Thread Carlo Pisani via cctalk

thus, MO drive units are not reliable?

2018-07-21 23:34 GMT+02:00 Chuck Guzis via cctalk :
> On 07/21/2018 02:12 PM, TeoZ via cctalk wrote:
>
>> I have old IBM MO Worm disks that are still readable, same with all my
>> MO disks (3.5" 130MB, 5.25" 1.3GB) but drives can be iffy. I would bet
>> that MO media will outlast us all while finding a drive to read them
>> will be a problem.
>
> I've got a few old PMC Apex 4GB disks.  I suspect that finding a working
> drive will be most difficult.  Heaven knows, mine died years ago.
>
> --Chuck
>

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-21 Thread Chuck Guzis via cctalk

On 07/21/2018 02:12 PM, TeoZ via cctalk wrote:

> I have old IBM MO Worm disks that are still readable, same with all my
> MO disks (3.5" 130MB, 5.25" 1.3GB) but drives can be iffy. I would bet
> that MO media will outlast us all while finding a drive to read them
> will be a problem.

I've got a few old PMC Apex 4GB disks.  I suspect that finding a working
drive will be most difficult.  Heaven knows, mine died years ago.

--Chuck

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-21 Thread TeoZ via cctalk

I had a home CDR back when they were over $1000+ new. The media turned out 
to be very reliable (and I have a bunch with gold, blue, green dye) and it 
still readable as long as you didn't scratch the optical reflective layer. I 
also used a laser printed paper cover which probably kept air out. I think 
the media had better quality control when a single CDR was $8 a pop then 
with a spool that costs $20. DVD recordable media was error prone if you 
used DL disks. I only used CDRW media for short term moving of files so I 
don't know how well they do long term. I have a BDXL Blueray drive I barely 
use since anything I need to get at is either online on my server of offline 
on a tape of some kind (LTO mostly but some DAT and AIT as well).


I have old IBM MO Worm disks that are still readable, same with all my MO 
disks (3.5" 130MB, 5.25" 1.3GB) but drives can be iffy. I would bet that MO 
media will outlast us all while finding a drive to read them will be a 
problem.


-Original Message- 
From: Carlo Pisani via cctalk

Sent: Saturday, July 21, 2018 11:14 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: how good is the data reliability with CD ROM and DVD RAM?

hi
yesterday I was shocked by a couple of videos on Youtube where guys
pointed out their negative experiences with CD ROM and DVD RAM as
media for their own backup.

They complained their data completely lost after 5 years of storage in
CD ROMs, pointing out that their CDs were perfectly conserved and kept
clean without scratches, but all the data is gone lost since the media
is unreadable.

This is what they said in the video.

I have a lot of backup here stored in CDs, and I have recently bought
an SCSI DVDRAM unit to create new backups in caddies DVD-RAMs (of
4.2Gbyte each)

what is your experience? 



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Re: how good is the data reliability with CD ROM and DVD RAM?


On Sat, 21 Jul 2018, Carlo Pisani via cctalk wrote:

what about MO? (magneto-optic disks)
- WORM (write once, read many)
- WMRM (write many, read many)
and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)
which of them lasts for the most?
MO units and disks are a bit costly
say >=50 euro for 4.5Gbyte R/W cartridge
and say >=500 euro for the driver unit (SCSI)


"M-Disc" has the longest longevity claims.

'course they're all extrapolation.  In a thousand years, it will be 
obvious that they are exaggerated.

Re: how good is the data reliability with CD ROM and DVD RAM?

2018-07-21 Thread Carlo Pisani via cctalk

what about MO? (magneto-optic disks)

- WORM (write once, read many)
- WMRM (write many, read many)

and what about magnetic-tapes? (e.g. DDS4, DLT, LTO2)

which of them lasts for the most?

MO units and disks are a bit costly
say >=50 euro for 4.5Gbyte R/W cartridge
and say >=500 euro for the driver unit (SCSI)

Re: how good is the data reliability with CD ROM and DVD RAM?


On Sat, 21 Jul 2018, Jim Manley via cctalk wrote:

The stability of the dyes is only part of the problem.  Even mass-produced
read-only optical media (e.g., movie/video content DVDs) can become
unreadable over time


Hence the necessity of ANYDVD, or equivalent.

Re: how good is the data reliability with CD ROM and DVD RAM?


On Sat, 21 Jul 2018, Al Kossow via cctalk wrote:

The edge of the disk is SUPPOSED to be sealed. On cheap media, you see it
oozing, and the aluminum oxidizing from the edge inward. This was pointed
out to me already in the late 90's.


Fortunately, unlike most spinning rust disks, the default is to start at 
the center and work out.  Therefore, discs that are not full will last a 
little longer.

Re: how good is the data reliability with CD ROM and DVD RAM?