Part 1 covered the beginnings of the SUC at Yeovil College in Somerset, the near-collapse of the SUC at the end of 1984, and its re-birth under a new nationally-based Committee in 1985-6.

Part II covered the years 1987-1991, during which time the new Committee established a regular Magazine, reliable and extensive Libraries, and some very useful hardware upgrades which included 80-column kits for the MZ-80A and MZ-700, and FD Eproms which enabled MZ-700 enthusiasts to use standard 5.25" Floppy Drives instead of Sharp‘s idiosyncratic QUICKDISK System.

Now read on......

SUC Library Developments 1992 - 2002

A complete set of Library lists was published in March 1992, in Vol.12 No.1. These showed that by that time most of our Library programs were stored on disk, leaving only a few programs for each machine that, for some special reason, were still stored on tape.

The one exception was the MZ-80K Library, which has always been the largest of our Libraries and the most difficult to manage. For this reason the MZ-80K Tape and Disk Libraries were kept separate for many years; and although this situation ended in 1990 when Alan Bunting added the MZ-80K Tape Library to his well-established MZ-80K Disk Library, his Library Notes for March 1992 revealed that a large number of MZ-80K programs were still stored on tape.

This situation was eventually resolved by Tony Clarke, who took over the MZ-80K Library from Alan Bunting in the summer of 1992. Tony‘s first decision, announced in Vol.13 No.1, was to devise a Disk Library List divided into 4 "categories" ( Games, Business, Languages / Utilities, and Special ). He then transferred all MZ-80K machine-code games from the Tape Library into the Disk Library, leaving a much smaller Tape Library, which he later transferred to a separate set of disks. The result was an MZ-80K Library that is so easy to operate that I have not changed its structure in any way since I took it over from Tony in the summer of 1996.

All the other Libraries have remained much as they were in March 1992, except that new disks bave been added from time to time. And they have seen only two changes of Librarian - the MZ-800 Library taken over by Paul Trainer in 1992, and the MZ-80A Library taken over by Peter Perkins towards the end of 1994.

Late in 1994 we acquired examples of Sharp‘s "X1", MZ-2500, and PC-7500 Computers from the Sharp factory in Wrexham. The "X1" came with a CP/M disk, and during 1996-1998 we acquired some essential software for the MZ-2500 and PC-7500. We were thus able to create an embryo Library for each of these machines. And of course we can also offer PD software for many of the more modern Sharp machines.

No other significant changes have taken place, and most of the current SUC Libraries are being run in the same way as they were in 1994, as shown by the table:

2) SUC Software Developments, 1992 - 2002

By 1992 we had sorted out the worst software problems, and possessed an improved Tape Basic for the MZ-80K and uninhibited disk-copying and disk-editing programs for all MZ-machines. We had also incorporated a vast array of excommercial programs from Apollo, Avalon, DCS, Knights and Sharpsoft into our Libraries.

From 1992 onwards our software development effort was spread over the following fronts ( in roughly chronological order ):

1. To improve the tape and disk Basics for ALL early MZ-Machines.
2. To enable MZ-users to utilise modern non-Sharp printers.
3. To provide improved UTILITY programs for copying disks and files, direct disk-editing, and disassembling Z80 code.
4. To investigate the use of 40-track 5.25" disk Systems on MZ-machines ( later extended to cover 80-track 3.5" disk systems ).

a) Improved MZ- Basics

We already had good Basics for the MZ-80K ( our own SP-5025.K2 on tape, and the Continental SP-7011 on disk ); and the original Sharp Basics on the MZ-700 and MZ-800 are more than adequate.

We therefore chose to start by concentrating on the MZ-80B and MZ-80A and, having no wish to reinvent the wheel, we decided to explore the possibilities of using the KNIGHT COMMANDER toolkits for the Sharp tape and disk Basics on the MZ-80B and MZ-80A.

KNIGHT COMMANDER Toolkits offer a flying start to any upgrade by adding RENUMBER, DELETE and a TRACE command ( TRON / OFF ). However, we met an immediate problem, because we had only 2 out of the 4 versions of KNIGHT COMMANDER that are needed to upgrade all the standard Sharp Basics on these machines. To be exact, we lacked the Toolkits for MZ-80B tape Basic SB-5510 and MZ-80A disk Basic SA-6510; and worse still we found it impossible to obtain them.

John Ibberson suggested that to solve the problem on the MZ-80B we should upgrade only disk Basic SB-6510 and allow it to "double" as a Tape Basic ( this is a practical idea on the MZ-80B, which has a higher tape baud rate than other MZ-machines ).

We were very glad to accept this compromise, as it speeded up the process considerably; and thus, towards the end of 1992, we were able to announce our very first SUPERBASIC, which we called SB-7510. For details see Vol.12 No.3 pp.27-29.

To solve the same problem on the MZ-80A we disassembled the MZ-80A tape version of KNIGHT COMMANDER, modified it to suit MZ-80A disk Basic, and then added many other commands from various sources. This involved a great deal of work, but by March 1994 we were ready to announce new MZ-80A SUPERBASICS SA-5575 and SA-6575, both with the usual COMMANDER features plus many other extras - for details see Volume 14 No.1 pages 35-37.

We then concentrated on bringing all these new disk Basics for the MZ-80K / 80B / 80A / 700 up to a more or less common standard; in the process we relocated the Master Basics on the MZ-80B / 80A / 700 disks to start on track 2 and removed long-standing BITMAP and RUN OBJ "bugs" on those 3 machines, and changed the 5.25" disk format on all four machines from 35 to 40 tracks - for details see Vol. 17 No.2 ( MZ-80A / 80B / 700 ) and Vol. 17 No.3 ( MZ-80K ).

Most of these SUPERBASICS were later incorporated into brand new SUC 3.5" 80-track master disks ( see ( d ) below ).

b) "C2" printer routines

As we were developing the SUPERBASICS mentioned above, we also created improved "Centronics" printer routines to go with them, so that Sharp MZ-enthusiasts could, if they wished, use modern printers. The ultimate "C2" versions of these routines enable this to be done without modifying the original Sharp printer card or circuitry in MZ-80K / 80B / 80A / 700 computers, and allow the printing of Sharp‘s special cursor characters, or of bit-image pages, as demonstrated on pages 8-9 of Vol.17 No.3.

c) Improved Utility Software

From the early days of the SUC, MZ-80K users had access to a "Utility" program called "DISK-UTIL". This very useful program, which is of french origin, can format and copy disks or transfer Sharp files of all types between tape and disk in any direction; but unfortunately it will not run on any other MZ-machine.

In 1994 John Edwards and I started off on what has turned out to be a mammoth task, developing MZ-80K "DISK UTIL" into an even more powerful utility called SUPERCOPY PLUS which is available in 4 different versions for the MZ-80K, MZ-80B, MZ-80A and MZ-700.

Unfortunately, the later stages of this development process were hounded by "bugs" which took a long time to come to light and have only just been traced and rectified. The full story is perforce related elsewhere in this issue, but in short we are hoping that the latest SUPERCOPY v.17 heralds the end of all these problems and gives us a set of reliable and very powerful copying programs.

Concurrent with the development of SUPERCOPY PLUS we created new versions of DISKEDIT that can read up to 40 or 80 tracks, and new Z80 Disassemblers called DISASM B800 and DISASM 8800. Any version of DISKEDIT or DISASM 8800 may be loaded and RUN in the work area of SUPERCOPY PLUS without disturbing that program in any way i.e. both these utilities may, if required, be used as if they were natural extensions of SUPERCOPY PLUS.

d) 40-track and 80-track disks

As noted above, SUPERCOPY PLUS can handle 35-track, 40-track, or 80-track disks. This has enabled us to standardise on a double-sided 40-track format for 5.25" disks, and a double-sided 80-track format for 3.5" disks.

In Sharp‘s 35-track 5.25" format for the MZ-80B / 80A / 700, track 0 holds the boot sector and the FAT, and tracks 1-2 are allocated to the Directory; but track 2 is not actually used by the Directory and is therefore wasted. The "UserArea" occupies the rest of the disk ( 67 tracks numbered 3-69 ) and as each track has a capacity of 4KB the effective disk capacity is 268 KB.

In our 40-track 5.25" format for the MZ-80B / 80A / 700, track 0 holds the boot sector and the FAT, and track 1 only is allocated to the Directory. The "UserArea" occupies the rest of the disk ( 78 tracks, numbered 2-79 ) and the effective disk capacity is therefore 312 KB.

In our 80-track 3.5" format, tracks 0 & 1 are used as on 40-track disks ( boot sector, FAT, and Directory ) leaving a "UserArea" of 158 tracks or 632 KB. However, the capacity of the FAT sector is only 500KB; so we use it to "map" tracks 2-126, and reserve the remaining 132 KB ( on tracks 127-159 ) for "hidden" files which are not accessible from the Directory but may be run by special machine-code programs ( e.g. at boot time ).

This arrangement is used on all our new 3.5" 80-track SUPERBASIC master disks for the MZ-80B / 80A / 700. The master Basic file starts on track 127 and is booted from there at start-up, leaving the 500KB on tracks 2-126 totally free for the "Directory Area‘ - not bad for computers that first saw the light of day in the early 1980‘s!

We have just started experimenting with 3.5" 80-track disks on the MZ-80K ( see MZ-80K section, this issue ). However, as MZ-80K disk routines work in "single density" the KB figures quoted above will be roughly halved ( our current estimate is 308 KB per disk, of which 250K should be mappable ).

3) SUC Hardware Developments. 1992 - 2002

During the preceding period 1987-1991 hardware developments occurred at a frenetic pace. By comparison the period 1992-2002 was very quiet, and saw only a few hardware developments, most of them relatively minor.

In 1992 Josef Riha introduced a C.G. Eprom to improve 80-column screen characters on the MZ-80B, and Steve Bass did likewise for the MZ-80A. These Eproms have never been listed as SUC "Hardware Kits" but they are mentioned here for the sake of the record ( see Vol.12 No.1 pp.36-39 ).

In 1993 die "Cenrronics" mods for MZ-80K / 80B / 80A / 700 printer circuits were republished WITH EXPLANATORY DIAGRAMS ( see Vol.13 No.1 p.7 ).

In 1993 we introduced an improved C.G. Eprom v.1.4 for the Sharp P3 printer ( see Vol.13 No.3 p.21 ).

In 1994 we introduced our own version of Sharp‘s Adapter Card MZ-1E20; this allows the MZ-800 to use Expansion Box MZ-1E06.

In 1996 we introduced a new 3-way FD Eprom for use with an MZ-80A disk card on the MZ-700 ( see Vol.16 No.2 p.7 ).

Since 1996 there have been no new SUC "Hardware Kits", and it is unlikely that any others will be considered necessary.

At this point, I have to admit that the writing of this history may seem like a bit of an ego trip. But on second thoughts it has reminded me, and I hope all of you, that the continued successful existence of the S.U.C. is the result of an incredible amount of dedicated work by a large number of people, spread over many years. And of course to the fact that our ancient Sharp MZ-computers just seem to carry on working when most of their contemporaries have gone to the Computer home in the sky.

As if to jog my elbow on that point, my "No. 1" MZ-80A recently emitted clouds of acrid smoke for about 5 seconds but then just carried on working as if nothing had happened. I know the cause of this fault, which in my experience can affect any piece of early MZ-equipment; it is the breakdown of the surge-suppressing capacitors that are connected across the mains input terminals of a typical Sharp MZ-type power-pack. Luckily, as I have now seen for myself on numerous occasions, these capacitors act as their own fuses by going open-circuit in clouds of smoke and leaving the mains still connected and the power-pack working normally!

This could be a design fault, but it could also be due to the fact that, in the part of Weymouth in which we live, the mains voltage fluctuates wildly and well beyond the +/-6% limit that the electricity supplier is supposed to observe. In fact, I feel that the fault is almost certainly due to over-voltage rather than poor design, and my faith in Sharp gear is not shaken by these events.

So I look forward to years of service from my trusty old MZ Computers which, as recently observed in these pages by others as well as myself, may still be used for simple W.P. applications with much less hassle than you get from the latest Microsoft "Office" System that needs MB‘s of RAM and GB‘s of Hard Disk.

Once we have sorted out the few remaining problems concerning the use of 3.5" disks ( which I regard as an essential step in preserving all our software ) I do not envisage much more software development, except perhaps in the area of converting 80-column software to run in 40 columns and thus avoid the need to modify original machines, which in the future will probably be more attractive to Collectors than machines which have been modified by a bunch of enthusiasts, be they ever so knowledgeable.

There is more than one way of looking to the future, and I know that many of our members are convinced that the answer lies in transferring all our software to a modern PC, after which it may either be exported back out in Sharp format as and when needed, or run on the PC under an MZ-emulator. The latter method is the obvious long-term solution, as future generations could then enjoy using a virtual MZ-machine long after the last real MZ-machine had gone to its grave.

But for me, as long as there are working MZ-machines around, the immediate future lies in converting to 3.5" disk drives and transferring all our valuable software into that format for safe keeping. We have made great strides in that direction with our BASIC software for the MZ-80B, MZ-80A and MZ-700, but there is still a lot of work to do to get 3.5" drives working reliably on the MZ-80K, and a lot of work to do on 3.5" CP/M software for all these early MZ-machines.

So there is plenty to get our teeth into, and the tasks involved should keep us happy for a few years yet.. .. .. .. ..