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cload.doc
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1986-04-02
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2KB
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48 lines
Binary files on CIS are stored in HEX format, similar to the more common
Intel hex format. Since these hex files are made up of normal seven bit
ASCII characters they may be captured to disk just like ordinary text files,
without needing to use a binary file transfer protocol, such as Xmodem.
1. Capture the file CLOAD.MSB to disk. The program runs under AmigaBasic
and will ask for input(hex) and output(binary) filenames.
2. Capture the target file to disk as Ascii. It should look like rows of
numbers, all starting with colons. Clean it up with STRIP or ED if necessary
-- no extra lines or characters allowed!
3. Run Cload on the captured hex file.
4. When Cload is finished the binary image file is closed, and should be
ready to run. If the initial upload of the file to CIS included ^Z's (1Ah) as
end of file markers, CIS may have merged them with the file. So check file
length.
That's all there is to it. Cload runs kinda slow, being in Basic and so
forth, but it has been tested on the hex file of Aterm4 and produced a file
identical to an Xmodem download.
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Error checking
A real problem with Ascii capture is the lack of real-time checksum or CRC
validation of the files being passed. The hex format that CIS (mostly) uses
has a checksum byte for every 24 data bytes, which gives some confidence in
the process if Cload completes its run without reporting any checksum errors.
This is poor consolation if you've spent 15 minutes on CIS getting the hex
file, only to have Cload complain of errors halfway through the translation.
If you know you have a noisy phone line, or see occasional {{{ characters on
your screen, try using 300 baud and/or hang up and call back. Sometimes
a second phone call gets routed through quieter lines or a better CIS node.
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Hex format
:1800A800268A0E9C0033C080F9007F0ABA5C01B109CDE0E96000505189
^^^ ^^ ^^^
||| || ||_checksum byte
||| ||_________________________________________________data bytes
|||_______________________________________________________address field
|_________________________________________________________# bytes this line