Re: Software for MS-DOS 1.25

From: Michał Pleban <>
Date: Fri, 06 Oct 2017 11:22:42 +0200
Message-ID: <>

Not quite. The correct format is:

* Semicolon character ":"
* Two characters encoding one byte in hex, denoting the number of bytes
to follow. Can be ether 00 (end of transmission) or 20 (transfer 32
bytes). So the file can be only transferred in 32-byte chunks.
* 32 hex bytes (data)
* One hex byte, a checksum of the 32 data bytes.

So it is similar to the Intel HEX format (code 83) except there is no
address field, and the number of bytes per line is fixed at 32.

Anyway, I can easily write a Perl program to send a file from the PC
side. I just need the files to send ;-)


didier derny wrote:
> Hi
> perhaps mos technology format... (check code 81)
> if you need to encode /decode it  I have a source code  (6502 assembler)
> Le 06/10/2017 à 10:44, Michał Pleban a écrit :
>> Hello!
>> I have dug out my Commodore 710 with the 8088 card and booted MS-DOS
>> 1.25 on it. It contains a program named RECV.EXE, which allows receiving
>> files over the RS-232 connection. The program is not documented but
>> after some debugging it turns out that it uses some simplified version
>> of Intel HEX format to transfer the files.
>> Now, I would like to download some software and try running it to see
>> whether it works. But after browsing some software archives I can see
>> that most DOS software is available for later versions of MS-DOS. Is
>> there any place where I can find applications that would run under
>> MS-DOS 1.25?
>> Regards,
>> Michau.
>>         Message was sent through the cbm-hackers mailing list
>       Message was sent through the cbm-hackers mailing list

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Received on 2017-10-06 10:02:59

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