ZX Computing


The Rotronics Wafadrive

Author: Colin Christmas
Publisher: SMT
Machine: Spectrum 48K/128K/+2/+3

 
Published in ZX Computing #17

Colin Christmas gets in the fast lane

Hardware

When fast access storage systems for the Spectrum were first introduced to us out here in User Country, everybody who could afford it went for a Drive, Disc or Micro - the members of the new elite would ask one another. What's it like? asked the rest of us taking a knife to the piggy bank.

Once again it seemed that the Spectrum was being raised to new heights. Those cassette recorders suddenly seemed to look quaint and outdated. Serious micro users, whether programmers or like myself just users and consumers of software and peripherals that look as though they mean business, recognised the potential of the new hardware.

One of the newest is the Rotronics Wafadrive. It is an impressive, neat and businesslike unit weighing some 900g and occupying a pride of place 230mm x 110mm x 80mm behind the Spectrum. It is connected to the expansion port by a sturdy ribbon cable. It uses two magnetic tape drives incorporated in the unit and small compact plastic cartridges or wafers, 67 x 45 x 6mm in size. These are available with three nominal capacities of 16K, 64K and 128K.

In practical terms, the 16K wafer is most useful when speedy access to limited amounts of information, small programs, is required. Rather like a pad or notebook, a 'try out area' before the finished data or program needs to be safely filed away and stored for future reference. Here, the other wafers fulfil their most useful function. Location of files on the 64K and 128K wafers or cartridges takes longer of course. Nevertheless with a search speed of 15 inches per second, both drives in the unit offer a maximum or 'worst' access time of 45 seconds using the 128K wafer.

The infinite loop tape (one sixteenth of an inch wide) inside each wafer is completed by a conductive splice which can be 'read' by the Wafadrive System when the drives are operating. LEDs are used to indicate the status of each drive and also when the power is on in the unit. The wafers are not easily damaged, handle well and can have the information stored on them protected in the same way as normal cassettes. The novelty of rapid access, storing and retrieving programs and data, takes a long time to wear off.

The Wafadrive operating system reserves about 2K of the Spectrum's memory for the two drive directories, which hold all the information about the wafers in the drives and the files stored on them. Also for systems variables, some of which can be usefully PEEKed and POKEd and also for the read/write buffers used by the system to hold sections of programs as they are read from or written to the wafers.

Extended Basic

The Operating System also provides the Extended BASIC commands which give access to all the extra facilities of the Wafadrive. Separate interfaces are not necessary with this unit. Rotronics have incorporated both the Centronics and RS232 Interfaces and along with the familiar expansion bus, ports for these are located at the rear. This means of course that the Spectrum can then drive any compatible printer. But via the RS232 Interface though in many ways unsatisfactorily slow, information can be received say from modems or even other computers.

Finally, a User Manual, a blank wafer and a word processor wafer are supplied with the unit. For those of us who choose to spend a lot of time over a typewriter keyboard producting vast amounts of material which then has to be documented and then filed, this latter is a useful facility which can be used as soon as the Wafadrive is connected up after unpacking. There again, word processor facilities have a special appeal if not function for me in any case. However, after using Tasword for a long time, it is my opinion that it is hard to beat.

The manual is easy to use for both beginner and expert, young and old alike. I liked its format and size, something like an office file or manuscript itself. More of a manual than an instruction book, it contains masses of information relating to the straightforward use of the unit but at the same time offers to stretch your knowledge and experience of both the Spectrum and BASIC. Not to mention a lot of useful and well expressed information about how the unit works.

Anyone going for a Drive needs to take this newcomer into account when the day comes.

Colin Christmas