p	The Rotronics Wafadrive was a peripheral for the ZX Spectrum, primarily incorporating an endless loop tape storage system but also a RS-232 and Centronics parallel port.

p	The Wafadrive had two drives, each accommodating a tape cartridge of up to approximately 128 kilobyte capacity. Drives could run at two speeds, high speed for seeking and low speed for reading/writing. Cartridges were physically larger than those of the ZX Microdrive, and were more similar in size to that of the stringy floppy, an endless loop tape cartridge for many early home computers.

p	The same mechanism was used in a similar device known as the "Quick Data Drive", designed to connect to the serial port of the Commodore 64 home computer



h4	AD from Your Sinclair Issue 5 - May 1986

p	What does a Wafadrive offer me that I can't get from my cassette ?
p	Speed's the obvious answer - it takes just 40 seconds to load Spectral Writer, the free word processor that comes with the Wafadrive from a 16k wafer. But the really big advantage is that you can store programs as files on a wafer. It's a real chore finding where you've put a particular program on a cassette, especially if you've got loads and loads of them on there.

p	So just how fast is a Wafadrive ?
p	Well, it all depends on the position of the tape in the wafer and it depends on the size of the wafer. But as an average, Sherlock on a 64k wafer takes 43 seconds to load. You can usually reckon on 2k of bytes going in every second plus the access time.

p	So it's not as fast as a microdrive ?
p	That depends as well. You're right, its not as fast at loading in the data. But, if you take into account the Wafadrives more friendly operating system and its easier command syntax, you'll probably find it takes you no longer to load in a program. All that "m";1; stuff goes straight out the window. It's just LOAD * "filename" and your away.

p	Yes, but what about reliability ? The reason i've been put off microdrives are all the stories about how unreliable the cartridges are.
p	Microdrive cartridges do have a finite life but there's no way you're going to wear out a wafer cartridge. There's more tape in a wafer than in a microdrive cartridge so it's under less stress. And the protective cover that slides across when the tape's not in use stops people putting their grubby fingers all over your tape.

p	What other advantages are there over microdrives ?
p	Other than performance, you mean ? Well now there's price. £45.95's what you'd pay for a microdrive without the interface 1 - the Wafadrive plugs directly into the back of your Speccy, of course. And remember, you get two drives on a Wafadrive just like on a professional system.

p	[Note: This article was published when the Wafadrive was selling at £49.95]

p	Why are there three different sizes of wafer cartridge ?
p	That's so you can choose the most appropriate size for the job you want it to do. The larger the memory, the more tape in the cartridge and the longer it'll take to access the files. So, there's no point in choosing a 128k wafer to store programs that you're loading frequently. Much better to develop your programs on a small wafer and then transfer them onto a 64k one that has planty of storage and medium access times. The 128k wafer is really only useful for archiving because of the longer access times. but when you do want an old program, you can quickly find it by CATing the wafer - try that with all your old cassettes.

p	Is the capacity of the wafers exactly 16, 64 and 128k ?
p	No, that's just for convenience. On average you could expect to get about 75k on a 64k wafer and anywhere up to 140 odd k on a 128k.

p	Can I connect any full size printer via the Centronics and RS232 interfaces ?
p	Yes - with the one exception of the MCP 40.

p	I'm used to word-processing with Tasword II and i'd like to continue with it - is it possible to transfer it to Wafadrive ?
p	Yes. You can get an information sheet that shows you how to do it directly from Rotronics. For anyone who hasn't used a word processor before, Spectral Writer will fulfil all your requirements.

p	Is it easy to transfer programs from cassette onto Wafadrive ?
p	If the programs are in Basic, you've got no problems. Just load them in, then save them onto the Wafadrive. Machine code programs can present more of a problem, especially if they're very large and don't leave around 2k for the Wafadrive Operating System. You'll find the transfer utility on the Rotronics Toolkit wafer very useful. It also includes routines to COPY to Epson printer, print graphics from Basic, a printer channel driver, a de-initialise routine and a file utility.

 

h4	Review from Home Computer Course 1985

p	The initial lack of a reliable, fast storage medium has meant that the Sinclair Spectrum has generally been overlooked as a machine for serious applications. The introduction of Sinclair's own Microdrive system, however, did not deter independent companies from producing storage systems such as the Rotronics Wafadrive.

p	Although the Sinclair Spectrum has become one of the most popular home microcomputers, it has been criticised in many quarters as being unsuitable for the 'serious' user. This has led to the Spectrum being dismissed as merely a games machine. Part of the problem has centred around the keyboard, which has not allowed the user to seriously consider using the machine for applications such as word processing and database management. Recently, Sinclair Research has attempted to defuse some of this criticism by launching the Spectrum +, which is fitted with a QL-style keyboard.

p	However, this is only part of the problem. Other difficulties hounding the supporters of the Spectrum as a serious machine are the computer's lack of standard interfaces and, more importantly, a fast and reliable mass storage system vital to any business or serious application for the hobbyist. Of course, with the introduction of Interface 1 and the Microdrive, the Spectrum could at least claim to have these facilities available. But the suspicion remained that the Microdrive was slow and unreliable. Furthermore, although the software base on cassette for the Spectrum is enormous, very little software has made the transition to the medium used by the Microdrive. In a situation like this, third party suppliers tend to step into the gap and produce alternatives. Here we look at the first of two contenders in the race to dominate the Spectrum mass storage market - the Wafadrive from Rotronics.

p	Unlike Interface 1 and the accompanying Microdrive units, the Rotronics Wafadrive is an 'al-in-one' unit. That is to say that both the peripheral interfaces and the mass storage units are enclosed in a single box. The advantage of this system is that the units do not have the trailing leads necessary for the Sinclair system, but it does mean that they lack something of the flexibility of the Microdrives, which can be daisy-chained together to expand storage space.

h5	The Look of the Machine

p	The Wafadrive is encased in black plastic with a 35-way ribbon cable ending in a cartridge slot fitted onto the Spectrum's expansion bus. On the front of the unit there is a pair of wafer cartridge drive slots. Between the slots are three light emitting diodes (LEDs). The central light is the power-on indicator, while the other two indicate drive activity.

p	On the rear of the drive unit are three edge connectors. On the left is a parallel expansion bus to allow Interface 2 to be connected. The centre edge connector is a Centronics-compatible interface to allow the drive to be attached to a parallel printer. The third is an RS232 serial port that enables the device to be interfaced with modems and other serial devices. These interfaces are an improvement over those provided on the Sinclair Interface 1, where, for example, one still has to connect a second Centronics interface to the units edge connector in order for it to run parallel printers. Unfortunately, however, users will still have to shop around for Centronics printers or modems with Wafadrive-compatible cartridge connectors.

p	The stringy floppy wafers specifically designed for the Wafadrive are in many ways similar to those used on the Sinclair equivalents. Inside each wafer is a continuous loop of video-type cassette tape with a width of 1.8mm. This tape is used instead of the more conventional audio tape because of its improved endurance and information storage capabilities. Once formatted, this tape can contain approximately 128 Kbytes of data, although Rotronics has also made 64 and 16 Kbyte cartridges available.

p	The cartridges themselves are approximately twice the width of the Sinclair waters, although they are of similar length and breadth in their protective boxes. This gives the Rotronics cartridges an appearance of miniature cassettes. The Wafadrive cartridges do not need protective casings, as the delicate tape is protected by an automatic sliding cover, similar in design to that on the Sony 3 inch microfloppy disks, although the Rotronics protection is made out of plastic instead of metal. On the left side of the wafer is a write protect tab, which can be snapped off. Of course, this tab cannot be replaced once it is broken off and users will have to find some other method of re-enabling their cartridges.

p	The commands used by the Wafadrive are more or less identical to those used on the Sinclair Microdrives. In both systems the command is followed by a '*', indicating that the external storage device is to be accessed. Examples of this usage are SAVE * , LOAD * and VERIFY *. However, the Wafadrive system does have slight differences because there are always two wafadrives present, as opposed to the numerous Microdrives that could be in the system. For example, when formatting a Sinclair wafer one uses the command FORMAT 'm' ;0; "name", where m;0 refers to the number of the Microdrive being used. When using the Wafadrive, the command is altered to FORMAT * 'a:name', with the a: referring to the name of the drive in use. Note that with the Wafadrive, there can only be a section a: or b:, whereas on Microdrive the number can be from zero to seven.

h5	The 'STREAM' System

p	The Wafadrive also takes advantage of the 'stream' system used on the Spectrum, in which there are 16 streams set aside for input/output management. Some of these are reserved for use by the screen and printer. However, channels four to 15 are available to other peripheral devices, and output streams to the Wafadrive are accessed by use of the OPEN # command. The Wafadrive also adds two extra streams to the system. Channels r and c (these letters can also be capitalised) are reserved for the RS232 and Centronics interfaces, respectively, and their usages are similar to the t and b channels - used when accessing the RS232 port on Interface 1.

p	There is an eight Kbyte ROM on board containing the extended BASIC commands used in controlling the system. This Wafadrive Operating System (WOS) is able to function by 'paging out' the lower eight Kbytes from the Spectrum's ROM, in much the same way that Interface 1 does. For example, the command LOAD * actually generates an error on the Spectrum: thus, when the BASIC interpreter encounters this command on the screen, it will call the error-handling routine. However, this call command will be intercepted by the WOS, which will then page in the Wafadrive ROM. This in turn will take over the error handling and interpret LOAD * as a command.

p	Compared with the Microdrives, the Rotronics Wafadrive is somewhat slower. For example, a 100 Kbyte Microdrive requires an average of 3.5 seconds to locate a piece of information, which is then transferred to the computer at a rate of up-to 19.2 Kbaud. The Wafadrive, on the other hand, can only manage a maximum transfer rate of 18 Kbaud, with a maximum access time of 45 seconds on a 128 Kbyte wafer. This is significantly slower, although this relative sluggishness is partially compensated for by its increased reliability. However, it must be noted that the Sinclair Microdrives were consistently faster than the Wafadrive in benchtest timings.

p	Although these access times are much faster than could possibly be achieved on cassette, they are still slower than comparable disk drive times. However, the Wafadrive, like the Microdrives incorporates a handy procedure when accessing the tapes catalogue. The catalogue is held on the first sector of the cartridge after the splice joining both ends of the tape together. Thus, to CATalogue a wafer, the drive has to wind the tape until it discovers the splice and can read the next suitable sector, After several seconds, the tape head will be past the catalogue sector. However, should the CAT command be entered again, instead of winding the whole of the tape round again, the drive will move for only a fraction of a second before displaying the catalogue again -it will be held in RAM once it has been called. Thereafter, the WOS merely checks to see whether the same wafer is inserted by looking at the next sector. If it is, the WOS will display the catalogue it already holds in RAM.

p	In keeping with the idea of implementing a mass storage system allowing the Spectrum to be used for more serious applications, Rotronics has included the Spectral Writer word processing program in the package. This is a relatively comprehensive system making full use of the Wafadrive. Functions such as reform paragraph, insert words and delete lines are called by using the Spectrum's Symbol Shift key in conjunction with 5 other keys. Other functions that access files held on wafer can be obtained by means of the options command: these include SAVE and LOAD text files from cassette or from Wafadrive. Spectral Writer is a fine word processor, although it does not enable you to set the line length on the screen. It is perhaps unfortunate that even when using a Spectrum+, the quality of the keyboard somewhat diminishes the Spectral Writer's efficiency.

p	Of course what makes or breaks any storage medium on a computer is the willingness of software houses to support it. At the moment this seems to be a serious drawback to the Wafadrive's success, since none of the major software houses are producing their programs on Wafadrive cartridges (this is also a problem that has been encountered by Sinclair itself). However, all is not lost for the Wafadrive user. At least one company is now producing a program that enables you to dump commercial software onto Wafadrive cartridges. This means that users will be forced to buy both the commercial cassette and a wafer to transfer it to, but a small price to pay for the vastly improved access times that are produced.

p	Another minor difficulty of the Wafadrive is the edge connectors on the back of the machine. Because they are non-standard, users must be willing to convert the interfaces themselves, or else they will have to look hard for peripherals with suitable connectors. But, although the Wafadrive does have its drawbacks, it is a finely made machine, and certainly a viable alternative to the Interface 1 and Microdrive provided by Sinclair Research.


h5	and another from SU:

p	<img src="b/massstr4.jpg">

p	The newest addition to the range of fast storage devices is the Wafadrive from Rotronics. That is an unashamed attempt to beat the microdrive in terms of the facilities it offers. For the price of £129.99 it offers two drives, Centronics and RS232 ports and, as an introductory offer, a word processing package, Spectral Writer by Softek, which in many ways rivals Tasword II.

p	On power up the Spectrum behaves as usual until the Wafadrive Operating System (WOS) is called. That is done by entering NEW *, at which point a copyright message is displayed and the system is ready to run. The syntax of the WOS has been well thought out, the normal Spectrum commands are used with the addition of the * to indicate the wafadrive rather than tape in the form:

pre	SAVE *"test"

p	That applies to all the normal tape commands except DATA. CODE can be made to autorun with the addition of a third parameter. The save name is converted to upper case by the system.

p	A system of defaults is used so the above line would save to the default drive; if that was the A drive and you wanted to save to the B drive the command:

pre	SAVE *"b:test"

p	would be used. The default drive can be easily changed using 

pre	CAT # "b:".

p	Other useful features are LOAD *, which loads the first program on the wafer, ERASE *"te" which will erase all programs starting with te and SAVE #"test" which will overwrite an existing program called test. That is useful when developing a program as usually any attempt to save using an existing name will cause an error to protect your programs from accidental erasure. CLS* will reset the ink, paper and border colours to the start up black and white.

p	It is not possible to save DATA in the usual way. A system of channels and streams, as used on the microdrive, are used with information being PRINTed to it and INPUT back. INKEY$ can also be used. MOVE is used to copy programs from one drive to the other. That will not work with programs which have been protected. FORMAT is used to format a new wafer and also to set the baud rate of the RS232 channel.

p	When the WOS is initialised it sets aside an area of memory for its own use. That contains a directory of both drives, a 1K buffer into which the sectors of data are loaded and space for the variables used by the system. That takes up 2292 bytes, each additional channel opened takes 1044 bytes and the Centronics interface a further 11 bytes. With so much space taken up, the number of commercial programs which can be easily converted is very small. Fortunately, Rotronics are working on filing and spreadsheet programs for business users and hope to he able to release games in the near future.

p	Wafers are available in three sizes -16K, 64K and 128K - and the smaller the capacity the quicker the system will work. Each wafer contains a continuous loop of tape and is designed so that a metal tab protects the tape when the wafer is removed from the drive.

p	When testing the system for speed a 64K wafer was used, being middle of the range and most useful to 48K Spectrum owners. Formatting the wafer takes 2.10 minutes; 73 sectors are found, one used for the directory leaving 72K available for storage. A maximum of 32 files can be kept on a wafer due to the design of the directory.

p	Using the test program it takes 14.55 minutes to save, due to the tape doing one complete revolution per save. It also gives an out-of-screen error after 22 saves as the drive prints what it is saving on screen. Loading in sequence takes 14.30 minutes and 14.08 when using a STEP of -1; when erasing it also takes 14.08 minutes. If the wild-card facility is used, i.e. ERASE *"*" it only takes 29 seconds because the tape only has to make one revolution. It would therefore seem that with a 64K water the minimum LOAD/SAVE time is about 30 seconds; a 64K block takes 40 seconds to save.

p	The manual supplied with the drive is well laid out and informative about the drives but lacking in respect of the ports. Apart from setting the baud rate it does not explain how to alter any parameters when printing. It appears that codes below 32 are not sent, other than 13 and/or 10 except by using CHR$, codes 32 to 164 are sent as normal and all tokens, codes 165 and above, aSUre expanded. That is adequate for most simple printing but some modems require parity and stop bits to be set (or not) on RS232 signals and printers can use differing line feed settings.

p	Overall the system has much to offer, proving more reliable than microdrive due to the design of the wafers, but the memory usage is very high and its speed slow compared to other available systems. It will probably be popular with business users where reliability is paramount and the Spectral Writer program is a good indication of what can be achieved. It is very similar to Tasword II in operation, whose text files can be loaded directly, with additional features such as page headings and numbers. It is rather quicker although some of the features are not so convenient, it tends to work on the text file globally rather than by paragraphs and so when justifying the file you cannot do so selectively. It can give odd results, as is found when there are two words on a line at the end of a paragraph and the file is justified. The words are moved to the far left and right rather than both to the left margin.

p	Provided you do not want to convert your own programs or can use the machine code method of using the screen, and you are not worried by the lack of speed then the two drives and ports are very useful. If you use the MOVE command to make back-up copies of wafers be prepared though to take a long coffee break.