Scor­pio News


January–March 1988 – Volume 2. Issue 1.

Page 30 of 39

nearly all corrupted. Since the corruption was ASCII text, I could read it and recognised it as some of the data which had been copied from the ICL disks.

Examination of the directory of the Winnie with SPZ.COM showed that the HLP files were still described correctly, with USER set to 10H, and block numbers from about 0193H upwards. The directory also still held references to some of the files transferred from the ICL disks, although they were of course marked E5 in the USER byte since they had been erased. The block numbers for these files however were in the same region as the .HLP files (0193H upwards). Obviously the transferred ICL files had been written to the area of the Winnie that had been holding the .HLP files.

It appears that when I used CP/M Plus to copy files to the Winnie from the ICL disks, CP/M Plus did not overwrite the .HLP file references in the directory, probably because the first byte was not 0ESH. On the other hand it did not mark the relevant .HLP file blocks from 0193H up as ‘used’ in its allocation map, probably because the first byte was 10H, an unrecognised user number. Consequently, as each ICL file was copied, CP/M Plus opened a new directory entry for it, but used blocks from 0193H to store the data. It took some time to recopy the ZCPR3 .HLP files back from my floppy backups and ‘USQ’ many of them en route, but at least no valuable files were lost.

I rarely revert to CP/M 2.2, and when I have done so the systems loaded have not in general been set up to access the Winchester. I suspect however that the problem could equally well arise when writing files to the Winnie under a CP/M 2.2 that allows Winchester disk access.

There are several ways around the problem, such as not using a USER above 15, or temporarily moving the files down to a lower user. The program MAKE.COM is ideal for this. Unfortunately it will not move them back, since it too baulks at a USER above 15. Other alternatives are possible such as not using the Winnie, and letting drive A: be a floppy. At least users of ZCPR3 (or any other system that makes use of USER areas above 15) who read this will now be aware of the problem.

Problems with the ZCPR3 Utility MCOPY.COM

MCOPY is, in common with most of the ZCPR3 utilities, extremely flexible, allowing a string of files and DU’s (or DIR’s) to be defined in the command line. The only thing that it will not do during copying is to rename a file, but this if permitted would be inconsistent with its other abilities. At times however, MCOPY does not behave correctly. I get SRC=DEST error messages, or No Files error messages. e.g.;

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