80-Bus News


January-February 1984, Volume 3, Issue 1

Page 11 of 55


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 deleting.

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 occurred.

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 GM833 “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 wumnexpected "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).

1. MDIS produces either Z80 or 8080 mnemonics as requested by the user but will default to the mnemonics used by the CPU in use.

2. Assembler source files may be produced. Current versions provide 100% compatibility with the Microsoft Macro-80 assembler.

3. Listing files may be directed to the CON:, PUN: or LST: devices or may be sent to a disk file.

4a 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.

56 A cross-reference listing may be supplied which lists each label and each address where the label is used.

6. 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


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