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Master 512 Forum by Robin Burton
Beebug Vol. 12 No. 8 January / February 1994

This month the Forum is a bit of a mixed bag, but I hope there's a bit to interest everyone and perhaps a timely reminder to anyone who hasn't given sufficient thought to what happens after April. We'll start with a point raised by a reader in response to my articles on PKZIP.


Thanks to Philip Draper (why is it always the same people?) for dropping me a line saying how much he'd enjoyed the PKZIP articles and that he'd learned a bit more about the program as well. Thanks too for reminding me about one quite important point about PKZIP which, frankly, I'd forgotten to mention. My excuse is that I use a hard disc and, naturally enough, lack of free disc space is rarely an issue. However, if you're restricted to floppies there's a point which you must bear in mind and which I completely failed to warn you about.

When PKZIP is compressing data it creates a temporary file which it uses as virtual memory, unless the total amount of data is very small so both the input and output fit into RAM. Obviously the quantity of output data is usually much less than the input, or there wouldn't be much point in the exercise, but equally the two together will often exceed the amount of free RAM in the machine, even in an expanded 512.

For example, if an 800K disc contains, say, 700K which compresses to 250K, added to the space for PKZIP plus sundry workspace the total's about a megabyte. This clearly won't fit into RAM and the source floppy doesn't have enough free space either, so unless you tell PKZIP how to handle the problem the job can't succeed and you'll get a 'disc full' message. Mind you, at least PKZIP does tidy up after such an event, but that sometimes adds to the confusion because you can't actually see what happened after the evidence has been cleared away.

By default PKZIP creates its temporary file on the current drive, so if in the above case the current drive contains too much source data there's no chance. However, if the current drive is the (empty) destination drive, or you tell PKZIP to put the temporary file on the destination disc everything will be fine. It's quite easy and it can be done in two ways. The most obvious way is another command line directive, although in this case the letter used, "-b", isn't as obvious as other PKZIP options. just add the '-b' option plus the temporary file's drive ID to the command like this:

PKZIP -a -bb: <archive-name>

which would tell PKZIP to use drive B: for its temporary file, assuming you're zipping from A:. Alternatively, you can permanently set the option as an environment variable, say in your autoexec.bat or in the security job itself, by the command: SET PKTMP=C: although this option is likely to be more useful with a hard disc.


To many of you the rest of the Forum will be well known, but in my experience a fair number are always caught napping when anything changes. Also, to be fair, there may be a few readers who've purchased second-hand machinery recently and who therefore haven't had the benefit of year's of BEEBUG magazine to learn about everything useful. It should by now be no secret that BEEBUG will cease publication after a couple more issues, in April.

Although it's sad for those of us who still enjoy our old machines, whether 512 or 6502, we must be realistic and face the fact that technology moves ever onward and in truth the old machine is now something of a dinosaur, no matter how useful you still find it and how much dinosaurs are in fashion at the moment. All credit to BEEBUG for continuing support so long after all others lost interest I say, but inevitably all good things come to an end.

No doubt a good many of you intend to continue to use your old faithful machine for some time yet. Why not? I for one certainly do. In fact I'll probably use mine until it breaks down and I can't get the bits to fix it, although the writing's already on the wall because many chips which are now out of production are already difficult to get hold of and some just aren't available at all. A bit of advice! DO NOT blow up your Tube ULA!!!

I don't know if you've considered all the implications of being 'alone' with your machine, but now's the time if you haven't done so before. Even forgetting potential hardware problems, there will no longer be any automatic regular source of information, hints, help, software or news. If you don't already belong to a computer club or user group and don't do something about it soon you'll be entirely cut off from all other BBC micro users after April. Likewise, those few people who can still supply software for the BBC or 512 will be cut off from you too, so don't leave it any longer to take steps to minimise this.

One excellent source of hundreds if not thousands of programs is Alan Blundell's BBC PD. I've mentioned BBC PD before and make no apology for doing it again. I have no connection with it and while modesty or good taste might prevent Alan from advertising his services too blatantly I suffer no such misgivings. For the committed BBC or 512 user there is a range of software in BBC PD's catalogue that would take you months to wade through and evaluate. An extra benefit is that costs are minimal. There's no excuse for being bored or dissatisfied with old software just because BEEBUG magazine is no longer published. Contact BBC PD now if you haven't done so before and help Alan to continue his sterling work. Of course you could be complacent and leave it a year or so before you do it, then you might find he's been forced to close down too owing to lack of support. If you're guilty don't say you weren't warned!


On a similar note Essential Software, run by yours truly, has been operating for several years now, since 1989 in fact, but still not everyone knows about it. I've not previously shouted about it in this column too much, but in fact even when regular reviews of 512 products or software were being published in BEEBUG some readers managed to miss them, even when they were on the page adjacent to 512 Forum! With only three issues to go, in addition to BBC PD I'm going to make sure everyone knows about Essential Software before it's too late. If Mike Williams disapproves perhaps I'll get sacked from writing 512 Forum, but I'll just have to take that risk.

There follows a brief outline of ES's 512 software range. You will see that prices have been reduced by about 50% as a final gesture to Forum readers from me (original price in brackets). If there's anything you want, now is the time to get it. This isn't (quite) a closing-down offer so there's no time limit on the offers as such and I'll supply everything, as well as still answering letters, as long as I can, but in purely practical terms I can't keep adequate stocks of EPROMs and floppy discs for ever and neither is it realistic to buy them in ones and twos 'ad hoc'. Inevitably at some point I'll have to call a halt, so this time next year could be too late. Memory use is shown only for programs that use 512 RAM, otherwise it's zero. All cheques payable to me please, and overseas orders add £1.00 to EPROM prices. If you need more info. please send an S.A.E. I also have the latest (and definitely final) update to PCCE and TXTMOUSE from David Harper, making both programs probably as near perfect as is possible in the 512 – yours for £1 with any ES order, or £2 on their own as before.

T H E  L I S T

RAMDISC (£16.95) £9.95
Allows a 512 ramdisc to be configured as any size from 10K upwards and as any drive. Includes AMNESIA, allowing deletion of the ramdisc without re-boot, and DISCID which allows switching of drive IDs plus suspension of any drive so it can't be accessed (and reinstatement!).

INTERCOM (£12.95) £6.95.
A command line editor with history recall. Commands can be recalled manually or by automated matching against a (wildcarded) search pattern. Word processor like editing during command entry. Configurable, memory resident, with 1k buffer uses 2.7K of RAM.

PFKEYS (£7.95) £4.95
Allows up to 30 user defined commands to be assigned to Shift/Ctrl/Alt function keys, so commands can be executed by a single key-press. Command can be saved to disc, re-loaded or amended as required. Configurable, memory resident, uses 3K of RAM.

HDSETUP (£10.95) £5.95
Partitions a winchester for any DOS partition from 1 to 32Mb. in 1Mb. steps, plus optimised directory sizing for smaller partitions.

SUPRSTAR (£14.95) £7.95
Gives an independent, true mode 7 screen for star commands, activated by hot-keys. Star commands issued previously are retained and the DOS screen plus the application or activity are preserved too. In SUPRSTAR normal BBC micro facilities include full BBC cursor editing, proper Escape processing, programmable function keys and correct MOS error handling.

GOBBC/512 (£14.95) £7.95
With SUPRSTAR £14.00 the pair.
Allows you to 'drop into' a completely normal BBC environment from the 512 and run any BBC task, then return to DOS where you left it. (NB. You must have SUPRSTAR for this.)

PRNTSCRN (£14.95) £7.95
Prints any DOS display (graphics text or both). Two programs, GRDUMP and PRTSCRN, both actioned by hot-keys hence can be used at any time. Configurable for 9 or 24 pin printers, using Epson commands, full IBM graphics support. Can also print SUPRSTAR screens.

CLMOUSE (£12.95) £6.95
Provides mouse cursor control for programs which don't normally use a mouse. Mouse buttons can be configured to generate any key press (defaults Return and Escape) and sensitivity can be adjusted as required. Settings can be saved to or loaded from disc. Trackerball compatible, application independent.

SCRNSAVE (£9.95) £5.95
Allows the DOS display to be saved directly to either BBC filing system. Filing system, drive and filename are all user definable. Triggered by hot-keys, so any display can be saved including those from within applications.

TRNSLATE (£14.95) £7.95
Allows any (PC or BBC) keypress to be generated by any key on any model of BBC micro. Includes numeric keypad for model B/B+, plus otherwise unavailable PC keys on all models, eg. right-shift, scroll-lock. Definitions can be saved to/loaded from disc and can include Shift and/or Ctrl modifiers.

MEMOPAD (£9.95) £5.95
A 'pop-up' notepad providing 10K bytes (4 A4 pages of text) of instant, independent note-taking storage. Contents of the pad can be saved to or loaded from disc, cleared or printed. Access by hot-keys, uses one BBC sideways RAM slot. Configurable for all sideways RAM types.

MISCELLANEOUS I (£11.95) £6.50

Select – a batch file menu driver providing the missing link between the user and batch files, allowing on-line selection of options in batch files.

Colordef – allows screen colours to be changed on hot-keys instantly. Change foreground or background colours whenever you like without access to the command line.

Suspend – pauses the 512. Suspend and resume are on hot-keys, stop the machine any time.

Lock – locks the machine from the command line with a user-entered password. The password is needed again to release the system, when LOCK reports if illegal access was attempted. Proof against all but Break.

Sound – allows full access to the BBC micro's sound facilities from DOS, parameters exactly as BBC Basic.

Envelope – allows sound envelopes to be defined in DOS, exactly as BBC Basic.

MISCELLANEOUS II (£14.95) £7.95

Keyclick – adds 'key clicks', like a PC. Clicks can be loud, quiet and switched on or off as required.

Oscli – * commands direct from DOS without clearing the screen. Much smaller and faster than STAR, plus no screen disruption, especially useful in batch files.

Cursor – allows changes to the size/flash-rate of the DOS cursor on hotkeys.

Scrnpres – blanks the display if the machine isn't used for a (userdefined) period preventing screen 'burn-in'. The display is reinstated by any key press.

List – is a cursor controlled, bidirectional scrolling text lister. Includes line-up/down, page-up/down, start/end of file, go-to line, ASCII filter, tab expansion, auto browse etc. A much more flexible replacement for 'TYPE'.

Lockword – like SUSPEND, but needs a (user-defined) password to release 512. When locked the screen display is blanked, perfect security if little fingers or big noses might interfere while you're away.

CPFS – 16K EPROM plus disc (£24.95) £14.95 The Co-Pro Filing System uses the (internal or external) 512 memory as a ramdisc for the BBC micro. CPFS is a full filing system (with extras) and can be used with any application. Transfer rate up to 125K bytes/sec. Up to 127 files in any number of directories.

CPFS+ -16K EPROM plus disc (£29.95) £19.95 Provides the facilities of CPFS plus a configurable printer buffer of from 4K to 1000K in 4K steps. Memory not used by the buffer remains available for CPFS files.

FASTBOOT (Sideways RAM) (£10.95) £5.95 EPROM (£14.95) £8.95
Boots the 512 in half the time (13-15 secs.) of a 640K disc and there's no need for a disc change from 800K to re-boot either.


That's all for this month except to remind you that if you want to write to me about any Forum topic, past or present, before BEEBUG ceases publication you'd better do that quickly too, and of course to wish you all a happy new year.

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