former case, the BDOS will print the message “Disk x: directory full” and in
the latter “Disk x: full”. In both cases, the message “Change disks? (Y/N/^C)”
will be displayed. If the user types ^C, the system will perform a warm boot.
If “N” is typed, a standard “disk full” or “directory full” code will be
returned to the CCP or calling program. If “Y” is typed, in the case of a full
disk, the currently addressed file will be closed. In either case, when the
BDOS is ready to proceed, it will display the message “Change disks then hit
any key or ^C”. If the user types ^C, the system will be rebooted. If not then
a new disk should be in the current drive and BDOSZ will reset the new disk to
make it R/W, log it in, create a new file on this disk with the same name as
before and continue with the write. The calling program will not be aware of
the disk change. BDOSZ will erase any file of the same name occurring on the
replacement disk unless it is R/O. In this case, BDOSZ will query before
As standard, BDOSZ sends a BEL character (ASCII 7) to the console device
for those users with a bleep facility to warn the user that an error has
BDOSZ has been in use now for about 12 months on three different
machines. No bugs have been found to date and the extra facilities provided
have proved invaluable.
[Ed. – a warning. Owners of Gemini systems with BIOSs of version 2.8 or
greater beware! These BIOSs do a check on power-up to determine if, and how
many (up to 4) Gemini
‘RAM-DISK’ boards are present. If any are present
the BIOS copies the CCP and BDOS to drive ‘M’ and modifies the BDOS to use
this for warm boots. Whether this will work with BDOSZ or not, who knows?]
The last piece of this software trilogy is for those of you tempted by
Henrys adverts for MDIS. For those who haven’t seen the ad., MDIS is a CP/M
disassembler with differences. It includes all of the excellent features found
in David Parkinson’s NAS-DIS and then some. The last version of MDIS to be
released was 2.1, version 2.2 was substituted after a small unexpected
“feature” was discovered. But now, version 2.3 is available with oodles of
extras. [Ed. – Since the time of writing, vers. 2.6 has appeared.] To those
who haven’t yet obtained a copy, you were possibly right to wait. For those
who have, never mind, upgrades are available at the cost of a copy charge.
Simply return it to the dealer you bought it from. Being somewhat biassed in
‘favour of MDIS, I wouldn’t attempt to review it but will provide a list of its
features (note that features in this case isn’t in quotes).
MDIS produces either Z80 or 8080
mnemonics as requested by the user but
will default to the mnemonics used by the CPU in use.
Assembler source files may be produced. Current versions provide 100%
compatibility with the Microsoft Macro-80 assembler.
Listing files may be directed to the CON:, PUN: or LST: devices or may be
sent to a disk file.
Labels are produced automatically. Labels are a four digit hex number
related to the address where the label is to be inserted. To make the
labels assembler compatible, they are given an alphabetic prefix. One of
four prefixes will be used for each label depending on whether MDIS
thinks the label refers to code, data, both or doesn’t know.
A cross-reference listing may be supplied which lists each label and each
address where the label is used.
Allows data areas to be specified as either hex bytes, ASCII, an address
table (with labels substituted for addresses) or a look-up table in the