Sunday 16 January 2022

UPLOAD.COM for Z80 CP/M - usage

 I feel very honoured to have written a utility which will be distributed as part of the system included with RC2014 kits with CP/M or ROMWBW.


Since upgrading my first RC2014 to CP/M, transferring files has been a bit tricky. My storage medium is a compact flash card, which I can't read with my modern computer system. I can "dd" it to make a backup, which is easy to transfer to a new card. But that doesn't allow me to put a file onto the card, or copy one off using my Mac.

There are methods of reading the CF card on a new system, but I've not made anything work for me. 

My favourite method of transferring my files onto the card is a combination of the DOWNLOAD.COM utility which comes with the CP/M system on the A: drive, and my own utility for creating a .PKG file. That's a hex format that works with the download utility. I've written about that here.  Spencer now provides a web utility which creates the same pkg file. 

The problem

That still leaves me unable to acquire a file that I've created on the RC2014. I tend to develop in Forth and assembly on my modern computer, transferring the files to the RC to run them, so I rarely create files there on the card. But there have been times when I've done so, and it would also be good to selectively back up files from the card rather than making an image of the whole thing.

Spencer asked me to have a go at writing UPLOAD.COM, the partner to DOWNLOAD.COM. I've written about the process of creating the utility separately if you're interested in Z80 programming and the CP/M's BDOS.

Using UPLOAD.COM

Sit UPLOAD.COM in A: alongside DOWNLOAD.COM

Then browse to any drive and use it like this:
A:UPLOAD MYFILE.COM

It is happy for you to give it wildcards in the standard way:
A:UPLOAD MAT?????.COM or 
A:UPLOAD *.* for every file in the directory, as I've done below.
Note that my terminal (minicom) doesn't do wrapping, and it doesn't allow me to select and copy the characters that are off the right-hand side. Those characters seem to be lost. The pkg format doesn't allow for breaks in the stream of hex characters.

The answer to this is to use the capture feature of your terminal program. In the case of minicom it's -C filename.  With that option, everything that comes to the console is also written to the file.
Here is my capture file, after UPLOADing all files in my B: drive. The process happens very quickly, and I was able to make a very convenient backup of every file in every drive on my CF card in a matter of minutes. 
It's very easy to copy and paste any of those files back into CP/M. The first line of the PKG is the instruction to use DOWNLOAD to put the file into the current drive.

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