Re: [M100] need help with ArcaneByte modem

[Mike Stein]

XON/XOFF was much more useful in 'the old days' although as you say it's
still useful in certain circumstances.

But yes, with so little space above the high water mark the M100 needs
either a bridge with a large buffer* or *a small packet  size if possible,
preferably one character just like 'real' RS232 (although that is somewhat
inefficient).

IIRC when Steve and I were doing some testing years ago I used a LANtronix
UDS-10 which was popular on eBay at the time and it did let you set the
buffer size to one character and worked pretty well at higher rates.

On Tue, Apr 27, 2021 at 1:28 AM John R. Hogerhuis  wrote:

>
>
> On Mon, Apr 26, 2021 at 7:04 PM Mike Stein  wrote:
>
>> WiFi adds an extra element to the problem because unlike
>> one-character-at-a-time RS232 the data is in uninterruptible packets; when
>> the M100 sends an XOFF to stop sending, the other end doesn't respond until
>> it's finished sending the current packet and since the M100 doesn't send
>> the XOFF until its buffer is almost full already you'll almost certainly
>> overrun the buffer.
>>
>
> The other end... I guess it depends on how the bridge device is written.
> It can arrive in big chunks, delayed chunks, etc... as long as there is
> enough buffer it still has to go through the skinny RS232 straw, which is
> supposed to be flow controlled. And that XOFF would be Model T -> device.
> There should be no delay right? Since the one that processes it is the
> bridge device not the machine on the other end of the TCP connection.
>
> Now if you think it is actually relying on dropping packets during XOFF so
> that the TCP window closes... yeah that has to go through a lot of back and
> forth logic to get the flow to stop.
>
> I think it should all comes down to how much buffer is available in the
> bridge device and how immediately the bridge is designed to respond to XOFF
>
> Like we found with Windows versus Linux, an OS can be very responsive to
> XOFF like Windows and everything works, or have bad buffering delays going
> on like Linux and it doesn't work with Model T at all.
>
> What I think delays XOFF is if the receiver of XOFF (the bridge in this
> case) gets "behind" AND processes the XOFF in-band as opposed to on
> arrival. So say a lot of bytes are buffered by the bridge device to be sent
> (because it is flowed off by the remote TCP socket), and then XOFF comes in
> behind that and is not processed until every byte in front of it gets
> processed.
>
> That's the problem with software flow control. To flow off the receive
> channel efficiently depends on the receiver of XOFF on the transmit channel
> processing XOFF out-of-band.
>
> This is why hardware flow control is by default, better... it is always
> "out of band" and not queued up on a separate channel.
>
> XON / XOFF can be efficient too but it depends on the implementation
> handling flow control as it comes in the port rather than after queueing
> and buffering.
>
> -- John.
>

Re: [M100] Memory release question

[Peter Noeth]

With .CO programs, they end up in memory twice: 1) At the top of memory you
protected using CLEAR sss,m command the documentation told you to do,
and 2) Stored in the File System area if you see its .CO file in the Menu.
BASIC programs (.BA) and document Files (.DO) execute "in place" so there
is only one copy of them in memory.

The reason is that the 80C85 processor doesn't have a "jump relative"
instruction, so all .CO programs are not "relocatable" and must execute at
the memory space they were assembled for, usually at the top of RAM.

This is a pain with the assembler as it is about 17K total. Just remember
to go to BASIC and do a "CLEAR 256, HIMEM" to release the upper memory copy
from RAM when you are through with the assembler.

Sometimes I use the CLEAR 256, m command to reserve the required RAM
space and use RUNM to load and run a program from tape into upper memory,
without saving the program to the File System. When I want to use it again
I can go to BASIC and use the CALL x command to re-execute it. (x
=  programs entry address). This saves RAM space, but if you have a crash
with your newly assembled program, which is pretty likely, it will take
time to re-load the assembler from tape again. And I avoid using the CLEAR
command until I am done with the .CO program.

Regards,

Peter

--
>
> Message: 2
> Date: Thu, 29 Apr 2021 10:35:10 -0400
> From: Charles Hudson 
> To: m100@lists.bitchin100.com
> Subject: [M100] Memory release question
> Message-ID:
>  ma9b6zlu-+b7jwwomfb2cvrvjj5nj1n3ze0tsgobdv...@mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> As noted, got the Model 100 assembler / debugger recently.  Installed on a
> Model 102 which has 32k and which, before installation, reported 28k free.
> Only 1 .BA program beside the standard applications.
>
> Loaded ZBGASM from tape and saved it to memory, after which the free memory
> was about 7k.  I thought that was a big chunk as the manual says the
> assembler occupies about 8.5k.  But it was in memory and I was able to
> invoke it from the menu so I proceeded to enter a sample program from the
> manual, assemble and run it, filling the screen with character 0FFH.
>
> Adding the sample program, SAMPLE.DO, and executable, SAMPLE.CO, didn't
> seem to reduce available memory much: still at 7K.  I deleted ("KILL"ed
> from BASIC) the two samples and the ZBGASM.CO files and was left with
> about
> 15K free memory.  Hmmm
>
> So I went back into BASIC and entered NEW (no change) CLEAR (no change) and
> tried hitting the reset button (no change).  As far as I can tell I have
> something occupying about 12k of memory that the system can't dislodge.  I
> suppose I could remove all power and turn off the memory backup but I'd
> rather think there is another way around this.  And I'd like to figure out
> what I'm doing to cause this memory "hole".
>
> I would appreciate any suggestions for figuring out how to remove it and
> restore max memory.
> Thanks,
> -CH-
>
> 

Re: [M100] Packet radio like it's 1987

[Tom Wilson]

Usually, you will make your own cable. Look up the pin out for your radio’s
connectors. Most mobiles have a TNC connector on the back, a mini DIN that
looks a lot like a PS/2 connector.

For radios without a TNC connector, you have to be creative. It usually
involves an interface box like a RigBlaster to connect to the microphone
and speaker jacks.

On Thu, Apr 29, 2021 at 2:21 AM Jeff Gonzales  wrote:

> Alex,
>
> Can you help me with a similar setup?  I think I found a TNC like yours in
> the garage.  Where do I get a cable for the radio?  What radio are you
> using?  Can I use a cheap Baofeng for this or do I need an HF radio?
>
> Thanks,
> Jeff
>
> On Wed, Apr 14, 2021 at 11:54 AM Alex ... 
> wrote:
>
>> Figure this would be a fun one to share with the [M100] list. :)
>>
>> I recently bought a big box of random ham radio packet gear which
>> included a bunch of old TNC modems and assorted cables. Unfortunately, it
>> turns out the quad serial port card in my desktop PC is dead.
>>
>> Enter the Tandy 102 to the rescue! I was able to test all 4 of the TNCs
>> on the air and sent a test email from the T through a local Winlink RMS
>> node.
>>
>> This whole exercise got me wondering if the built-in Bell 103 modem could
>> be adapted for HF packet radio use. Has anybody tried that yet?
>>
>> Pictured in the attached photo is the Tandy 102 hooked to a MFJ 1274
>> modem, monitoring Network 105 traffic on 7104khz.
>>
>> -Alex
>>
> --
Tom Wilson
wilso...@gmail.com
(619)940-6311

[M100] Fwd: Memory release question

[Charles Hudson]

-- Forwarded message -
From: Charles Hudson 
Date: Thu, Apr 29, 2021 at 10:35 AM
Subject: Memory release question
To: 


As noted, got the Model 100 assembler / debugger recently.  Installed on a
Model 102 which has 32k and which, before installation, reported 28k free.
Only 1 .BA program beside the standard applications.

Loaded ZBGASM from tape and saved it to memory, after which the free memory
was about 7k.  I thought that was a big chunk as the manual says the
assembler occupies about 8.5k.  But it was in memory and I was able to
invoke it from the menu so I proceeded to enter a sample program from the
manual, assemble and run it, filling the screen with character 0FFH.

Adding the sample program, SAMPLE.DO, and executable, SAMPLE.CO, didn't
seem to reduce available memory much: still at 7K.  I deleted ("KILL"ed
from BASIC) the two samples and the ZBGASM.CO files and was left with about
15K free memory.  Hmmm

So I went back into BASIC and entered NEW (no change) CLEAR (no change) and
tried hitting the reset button (no change).  As far as I can tell I have
something occupying about 12k of memory that the system can't dislodge.  I
suppose I could remove all power and turn off the memory backup but I'd
rather think there is another way around this.  And I'd like to figure out
what I'm doing to cause this memory "hole".

I would appreciate any suggestions for figuring out how to remove it and
restore max memory.
Thanks,
-CH-

Thanks to you both for your responses:  As a follow-up to my first post I
brought up the M102 and from a BASIC prompt typed ?HIMEM.  49xxx was the
response.  ?MAXRAM showed 62,960 bytes.  Clearly this was the problem.

I had consulted my *TRS-80 Model 100 Portable Computer* manual on the use
of CLEAR (p.129), where I read: "10 CLEAR clears all variables, closes open
files, sets the available string space to 256 bytes, and releases all of
available memory to BASIC."  I misunderstood the use of "available",
because a note earlier on the page says: "However, if you have protected a
portion of *high memory* in a previous program, BASIC keeps this part of
memory protected until you CLEAR it."

The magic incantation?  CLEAR 100, MAXRAM.  I now have 29,270 bytes free,
according to the OS.  Q.E.D.
Thanks, all for your help.
-CH-

Re: [M100] Memory release question

[Stephen Adolph]

what is HIMEM?
type
?HIMEM



On Thu, Apr 29, 2021 at 10:35 AM Charles Hudson  wrote:

> As noted, got the Model 100 assembler / debugger recently.  Installed on a
> Model 102 which has 32k and which, before installation, reported 28k free.
> Only 1 .BA program beside the standard applications.
>
> Loaded ZBGASM from tape and saved it to memory, after which the free
> memory was about 7k.  I thought that was a big chunk as the manual says the
> assembler occupies about 8.5k.  But it was in memory and I was able to
> invoke it from the menu so I proceeded to enter a sample program from the
> manual, assemble and run it, filling the screen with character 0FFH.
>
> Adding the sample program, SAMPLE.DO, and executable, SAMPLE.CO, didn't
> seem to reduce available memory much: still at 7K.  I deleted ("KILL"ed
> from BASIC) the two samples and the ZBGASM.CO files and was left with
> about 15K free memory.  Hmmm
>
> So I went back into BASIC and entered NEW (no change) CLEAR (no change)
> and tried hitting the reset button (no change).  As far as I can tell I
> have something occupying about 12k of memory that the system can't
> dislodge.  I suppose I could remove all power and turn off the memory
> backup but I'd rather think there is another way around this.  And I'd like
> to figure out what I'm doing to cause this memory "hole".
>
> I would appreciate any suggestions for figuring out how to remove it and
> restore max memory.
> Thanks,
> -CH-
>

Re: [M100] Memory release question

[Bert Put]

Hi Charles,

You may have some data in the clipboard.  Open any text file, then
select one character and "COPY" it.  That should reduce the clipboard
(copy buffer) size to one byte.

Also, what parameters did you give the CLEAR command?  Just "CLEAR" by
itself probably won't do anything.  You probably need something like
"CLEAR 0".  Hope that helps.

Regards,Bert

On 4/29/21 9:35 AM, Charles Hudson wrote:
> As noted, got the Model 100 assembler / debugger recently.  Installed on
> a Model 102 which has 32k and which, before installation, reported 28k
> free.  Only 1 .BA program beside the standard applications.
> 
> Loaded ZBGASM from tape and saved it to memory, after which the free
> memory was about 7k.  I thought that was a big chunk as the manual says
> the assembler occupies about 8.5k.  But it was in memory and I was able
> to invoke it from the menu so I proceeded to enter a sample program from
> the manual, assemble and run it, filling the screen with character 0FFH.
> 
> Adding the sample program, SAMPLE.DO, and executable, SAMPLE.CO
> , didn't seem to reduce available memory much: still
> at 7K.  I deleted ("KILL"ed from BASIC) the two samples and the
> ZBGASM.CO  files and was left with about 15K free
> memory.  Hmmm
> 
> So I went back into BASIC and entered NEW (no change) CLEAR (no change)
> and tried hitting the reset button (no change).  As far as I can tell I
> have something occupying about 12k of memory that the system can't
> dislodge.  I suppose I could remove all power and turn off the memory
> backup but I'd rather think there is another way around this.  And I'd
> like to figure out what I'm doing to cause this memory "hole".
> 
> I would appreciate any suggestions for figuring out how to remove it and
> restore max memory.
> Thanks,
> -CH-

[M100] Memory release question

[Charles Hudson]

As noted, got the Model 100 assembler / debugger recently.  Installed on a
Model 102 which has 32k and which, before installation, reported 28k free.
Only 1 .BA program beside the standard applications.

Loaded ZBGASM from tape and saved it to memory, after which the free memory
was about 7k.  I thought that was a big chunk as the manual says the
assembler occupies about 8.5k.  But it was in memory and I was able to
invoke it from the menu so I proceeded to enter a sample program from the
manual, assemble and run it, filling the screen with character 0FFH.

Adding the sample program, SAMPLE.DO, and executable, SAMPLE.CO, didn't
seem to reduce available memory much: still at 7K.  I deleted ("KILL"ed
from BASIC) the two samples and the ZBGASM.CO files and was left with about
15K free memory.  Hmmm

So I went back into BASIC and entered NEW (no change) CLEAR (no change) and
tried hitting the reset button (no change).  As far as I can tell I have
something occupying about 12k of memory that the system can't dislodge.  I
suppose I could remove all power and turn off the memory backup but I'd
rather think there is another way around this.  And I'd like to figure out
what I'm doing to cause this memory "hole".

I would appreciate any suggestions for figuring out how to remove it and
restore max memory.
Thanks,
-CH-