Software Review: MicroSPAN

Transcribed from the printed issue; not yet reviewed. Read it in the PDF of the issue, page 41

Introduction¶

MicroSPAN is a self-teaching system for computer-aided instruction in APL, written by MicroAPL. The version we used was MicroSPAN/PC. The package is held on three disks, containing the workspace and two files. It requires a PC with an APL chip, at least one floppy disk drive and 256 bytes of RAM. Apart from the package itself you need APL* PLUS/PC Release 2.0 or above.

MicroSPAN is meant for a variety of people ranging from the computer illiterate to those who know almost everything – MicroSPAN has set itself a difficult task if it is to be simple enough for the ignorant without being simplistic for the educated. Unlike practically every package I have come across it does succeed; I think this is because it behaves like a courteous Englishman rather than a matey American, so that you do not mind being told things you already know because it is so polite and does not patronise you! MicroSPAN is fun to use, mainly because it is written with a sense of humour. Reassuring words lead the student through seemingly obscure matrix operations, and a generally light-hearted attitude (often at the expense of APL programmers) helps them to feel like carrying on, no matter how bemused they are by the latest set of squiggles and dashes.

Presentation¶

The course is presented in the form of an electronic book, with chapters and sections; there is a good index which enables you to jump straight into the section in which you are interested. I have not worked out how it achieves the effect, but it seems to present all the topics of APL in such a sensible logical order that it all seems very simple; perhaps this merely reflects my training which was a selection of bits of courses plus Gilman and Rose?

As well as clear explanations of the operations, you are presented with examples which execute before your very eyes: a test at the end of each chapter is mainly composed of multiple choice questions. There are good facilities for going backwards, forwards and jumping around the book, so that the student may revise any topic he wishes. On completion of the course our programmers are fully competent to produce their own functions and programs.

Why use a PC?¶

Our requirement was for a package for use by experienced programmers with no knowledge of APL, or of PCs, which would enable them to write and amend APL programs on an IBM mainframe. Secondary requirements were that it should be efficient in teaching a comprehensive subset of APL; have a reasonable number of examples; not take too long to complete; and need minimal effort on the part of the training advisor. We were not looking particularly at PC packages, but this one seemed to meet all our requirements.

Although our students were eventually to use APL on a mainframe we considered the advantages to be gained from using a PC would compensate for the disadvantages. Because PC time is not chargeable the student feels free to experiment and revise; in addition there are actual cost savings. Once in APL there is no noticeable difference between PC and mainframe. We do, however, handicap our students by giving them a keyboard with red stickies which are not all on the correct keys …but they never complain.

The last two chapters in MicroSPAN deal with PC enhancements and PC files, but none of the earlier chapters are PC specific.

Student Performance¶

Most of us find it difficult to remember how long a course takes, but one of our programmers has it accurately recorded! He took 710 minutes to do the first eight chapters, and found that sessions of an hour a day suited him best.

My personal benchmark for any text or package on APL concerns the way in which it describes inner products; in order to pass my test it must introduce matrix multiplication with its row-into-column rule – MicroSPAN passed with flying colours. Without being overtly mathematical it conveys the flavour of APL as a language for expressing mathematical concepts. I looked for, but could not find, a single mistake.

My criticisms all lie in the field of presentation; although these do not detract from the usefulness of the course they do distract the student, and should respond to fairly trivial amendments. Firstly, although we used a colour screen I had a strong suspicion that some parts of the course had been originally in mono and the colour was added later, and not very skilfully. Secondly, instructions to mount a new disk do not always say which disk; changing disks is enough of a nuisance without having to think which one goes next! Thirdly, in common with most training packages it makes noises, and while there are instructions for switching off the menu bleep, there are no such instructions for preventing the electronic fanfare or raspberry which follows each of the student’s answers (although it can be done). In a professional, open-plan programming office it can best be considered as an embarrassing (noise) nuisance, and at worst deters the student from doing the questions at all!

Summary¶

MicroSPAN is one of the best automated training packages I have come across, both in presentation and in its scope. For anyone with access to a PC it should certainly be considered as a possible APL tutor and as a reference manual.