In theory, CP/M was meant to provide a common operating system for all microcomputers, so that a given program could be run on all machines. In practice, things did not work that way, because the makers of CP/M machines made no effort to adopt a common disk format; there were hundreds of different makes and models of CP/M machines, and virtually every one had its own disk format. As a result, a formatted disk was useable only on the make and model of computer for which it was intended. This meant that, although a particular piece of software could be said to run ‘under CP/M‘, any actual physical copy of it, on a disk meant for a particular machine, could not be used on any other make or model of Computer.

This was an intolerable state of affairs, but it remained the general rule until IBM ( or was it Microsoft ? ) introduced MS-DOS, with its common disk format for virtually all machines. Ordinary non-technical users of CP/M machines could not even move a simple document disk from one make or model of computer to another.

For those in the know, the problem was solved by programs which rewrote the BIOS of the host CP/M machine to handle disk formats other than its own. Some of these programs, such as those for the MZ-3500 and MZ-700, were supplied as part of the CP/M system for the machine, and offered a limited range of alternative formats. Other programs offered a wide range of alternative formats, and were sold commercially, as ‘utility‘ programs meant for ‘experts‘.

lt is important to realise that ANY such program is tailored for the BIOS of its ‘host‘ computer, and will not work on any other machine. Thus, the programs which are supplied as part of the CP/M Systems on the MZ-3500 and MZ-800 only work on their respective machines; and if you buy a commercial program, it MUST be tailored specifically for the machine on which it is to run.

My favourite commercial program is ‘UNIFORM‘. I first obtained it for my Epson QX-10, and it offers 77 disk formats including the one used by MZ-80B CP/M, and standard 360K MS-DOS. More recently, I obtained two other versions of ‘UNIFORM‘ for my Tandon PC; one can handle CP/M disks from the MZ-80B, and the other can handle CP/M disks from the PC-3201 and the MZ-800. With some sleight of hand, I have combined and extended the two PC versions to make my own personal version of ‘UNIFORM‘. Its 285 options include all Sharp CP/M-80 DD formats that I know of, plus MZ-5600 MS-DOS 720K and Epson QX-10 280K and 400K. I refer to it as ‘UNIFORM v.113S‘.

The only Sharp-CP/M disks I cannot handle with ‘UNIFORM v.113S‘ are the single-density disks used by Crystal CP/M on the MZ-80K, and the CP/M-86 formats for the MZ-5500 / 5600 ( but I can handle the MZ-5500 CP/M-86 format with a PC program called ‘ALIENC‘ ).

I should perhaps mention other programs which offer facilities similar to those in ‘UNIFORM‘ and ‘ALIENC‘. One, called ‘ALIENM‘, also runs on a PC, and offers a group of ‘weird' MS-DOS formats. Another PC program is ‘TELEDISK‘, much favoured by John Edwards; he has built up a personal library of Sharp formats, and I believe it includes MZ-80K single-density CP/M, and MZ-5600 CP/M-86.

However, I shall restrict myself, below, to a summary explaining which formats I can handle personally, in Weymouth. In short:-

This CP/M version of ‘UNIFORM‘ was the first program I ever used to handle ‘foreign‘ disk formats; it has two modules. The first sets up drive ‘B‘ to the selected ‘foreign‘ format, and the second allows you to move files between QX-10 280K CP/M format and MS-DOS 360K format. The ‘foreign‘ module offers 77 formats, including the MicroTechnology 350K MZ-80B CP/M format, which covers MZ-80A CP/M and the 52K CP/M which members of the SUC invented for the MZ-700.

M-T‘s MZ-3500 CP/M can handle CP/M disks from the MZ-80B / A / 700 and the PC-3201. For details see the MZ-3500 section, this issue.

DISKDEF.COM allows DRIVE B to be set up for CP/M disks from the MZ-80B / A / 700, MZ-3500, MZ-5500, and early IBM ( CP/M-86 ) machines. The MZ-3500 option also accepts PC-3201 CP/M 35-track disks, which use the same format ( but the free space is miscalculated ).

The PC version of UNIFORM is ‘resident‘. Once invoked, it adds a 'logical‘ drive which may be set to any ‘foreign‘ format. On my Tandon PC, ‘A‘ is 5.25“, ‘B‘ is 3.5“, and ‘C‘ and ‘D‘ are the HD. The extra ‘logical‘ drive ( physical ‘A‘ ) is therefore called ‘E‘ and it may be set ( inter alia ) to MZ-80B / A / 700 CP/M, MZ-3500 CP/M, PC-3201 CP/M, MZ-800 / 700 PCP/M, or QX-10 CP/M ( 280K or 400K ).

‘ALIENC‘ is run from DOS whenever you want to use it; you select a format, and a drive number ( n, 0 - 4 ). ‘ALIENC then sets up that drive as the default logical drive n: and waits at the n> prompt, when ‘?‘ produces a HELP screen explaining all the commands. On my Tandon, ‘ALIENC‘ offers most Sharp formats, but the MZ-3500 option will not take M-T CP/M or PC-3201 disks and the MZ-80B and MZ-800 options err on free space. However, the MZ-5500 CP/M-86 option is all correct, and useful. When finished, type QUIT to exit to DOS.

‘UNIFORM v.113S‘ can handle all Sharp CP/M-80 and Epson QX-10 formats, and MZ-5600 MS-DOS format, on my Tandon PC. So I can now read all my old document disks, in many different formats, on one machine. In abort, all the articles and other SUC publications I have ever produced, or received from others, can now be revised or updated on my PC. All I need now is a laser printer !

The Epson QX-10 version of ‘UNIFORM‘ proved very useful, some years ago, in enabling me to transfer CP/M software from the QX-10 onto the MZ-80B, and thence onto the MZ-3500, PC-3201, and MZ-800. lt also allowed me, in extremis, to disk-edit MZ-5500 MS-DOS ‘EXE‘ files before I ever had access to a PC and ‘PCTOOLS‘. All in all, I regard ‘UNIFORM‘ as one of the best utilities ever invented.