Memory: 16K
Price: £7.95

TT-S from Timedata is a collection of five programs for the 16K/48K Spectrum, designed to make life easier for programmers. It was written originally by Timedata programmers for their use.

GAMMA is 4,410 bytes of re-locatable code which give you an extra 10 keywords and also prevent you entering NEW or deleting a line accidentally. The extra keywords are AUTO, which generates line numbers automatically; RENUMBER; block DELETE; MOVE, FIND a string; TRACE on and off; FREE, the number of free bytes; VARIABLE dump; and HELP, which lists the new keywords.

To enter one of the new commands Symbol Shift and 0 are pressed to change to a T cursor, followed by the relevant key. The program can be used with a Microdrive.

SCREEN is a useful highres drawing program with all the usual commands, such as fill and text insertion, but excludes circle. UDG displays six UDGs in an enlarged 3 x 2 block. As you change them you can also see the real size display change.

TAPE is a standard tape head reader which gives details of the type of program, name, length and auto-run line number. RAM is a memory test program which tests each bit in each byte of user RAM, including the screen. The collection has something for everyone and is well worth buying.

TALKING OF TOOLKITS

Essential for software development, toolkits are often billed as the programmer's 'tools of the trade'. Peter Freebrey takes five such packages on the bench and examines whether they fulfill their promise.

A toolkit is a utility program that will take a lot of the sweat and worry out of writing and debugging your own programs; often too, it will give commands and routines the computer manufacturer should have installed in the ROM in the first place! These are likely to include: Renumber, Delete, Free Memory, Find, List Variables and Alter. You may find one or two are missing, but in that case, there'll probably be instead some other useful goodies tucked away in that binary brainbox. And, as you'll see from the table included in this article, some toolkits have a larger range of commands than others. But, much like computers in general, put a number of them side-by-side and you'll be able to say that each should ideally have something that one of the others has got. That's life, I guess!

So, what are these routines for? Well, say for instance that you've written a long program without keeping an absolute record of the variable names you have used (tsk, tsk). In that case, FIND DX (for instance) will jump to the rescue and list out the lines where you used the variable DX. No can find? Great... in that case you can use it as your next variable.

Have you ever kept rigidly to a line spacing of 10 - 10, 20, 30, 40... - only to find that you need to insert some lines between lines 110 and 120? Well, no problem if there are just a few of them - 111, 112, 113, etc. But what if you need to insert a routine of 20 or so lines? Yes, of course you can change the line numbers, but at this stage it's all too easy to overwrite an existing line and... whoops, another chunk of debugging to deal with. RENUMBER is the simple and safe (usually!) way out.

Then again, perhaps you have a big program and you want to know how much memory you've got left. You can remember reading in that book you bought last Saturday about some POKEs and PEEKs that will tell you but, now where was that page? In fact, it's much easier to just type FREE (or some such) and see the answer immediately. All these are often used applications of the ubiquitous toolkit.

If you're in the market for a toolkit (or I've just convinced you that you should be!), you probably won't be surprised to find out that there are a number of toolkits for the Spectrum, and two of the five reviewed here are readily available over the counter in two of the larger chain stores. The other three can be ordered through the post if you're unable to find them in good shops.

The table at the end lists the routines available from each toolkit and provides a quick comparison of what each offers. But this is by no means the whole story, for ease of use is an important factor too. One toolkit from a year or so back required something like 'RANDOMISE USER 63338 a,b,c,d' to be typed in each time you wanted a specific routine; certainly it provided the goods, but it was also a case of getting the instructions out every time you wanted to use it! Then there's the matter of 'friendliness' of operation... is it possible to irrevocably change (or ruin) your program by just a simple mis-key? Sometimes to get the set of routines you want, you have to accept a compromise. I'll be dealing with each toolkit individually, pointing out not only its better points but the rough edges as well.

TT-S TIMEDATA

This tape from Timedata not only has a toolkit (called Gamma) that's much like the foregoing, but also four other utility programs - high resolution screen drawing, user-defined graphics creator, a tape header analyser, and a machine code memory test program. With this, you certainly get your money's worth!

The toolkit program comes first and you load it by keying LOAD "". This auto-RUNs and immediately sets two general safeguards - NEW is inhibited so you can no longer accidentally erase your program and it's impossible to overwrite an existing program line. Thus you have an excellent line editor; type in the line you wish to EDIT, press any keyword key and the line is displayed at the bottom of the screen. If required, it may be deleted by either DELETE or by typing in the line number and keying Enter.

Once you've invoked the toolkit by hitting the '0' key with the Symbol Shift key pressed, routines are all single key entries. AUTO line number and DELETE need no comment. FREE not only displays the free memory available, program and variable space but also the current values of the system variables; it also shows the current user-defined graphics characters. HELP displays the toolkit routines and their associated keys; FIND will hunt out occurrences of a specified string starting its search from a specified line number (defaulting to line 0 if no start is given).

Only the line numbers are displayed - no program lines are LISTed. RENUMBER will only work within a sequential block of lines (renumbering all GOTOs, GO SUBs, etc). MOVE is superior to other versions in that it also renumbers all references to the new block of lines (providing they're not in the form of GOTO 330+R). In fact MOVE is so good one wonders why Gamma has got both RENUMBER and MOVE! Both commands are 'intelligent' in that they'll close up the specified line increment, even where you've not allowed sufficient space! It's also possible to have lines going up to line 16000(normal maximum is 9999). The first two digits of these extended lines are replaced by a non-numeric character and they can't be edited (although they can be RENUMBERed or MOVEd). References to these lines elsewhere will have to be changed for the program to function correctly - for instance, GOTO < 350 becomes 12350.

The keyword, VARIABLES, LISTs variables but arrays are only shown by their dimensions. F/N is put against variables used in FOR... NEXT loops together with the line number of the FOR statement. TRACE is an interesting variant in that not only can you select the delay (from single-step up to about five seconds) but in addition to displaying the current line number, it'll also show the current values of specified variables.

All the TT-S programs will run on either 16K or 48K Spectrums, with or without Interface 1 and Microdrives. Routines are even provided that enable you to copy these programs on to a Microdrive wafer.