In Which Franco Frey concludes his survey of fast storage media, that allow you to get more out of your Spectrum. Well, more out in a given period of time. And more in, too. That’s what Fast Storage is all about really.

LAST IN THE SERIES of fast storage media is the Timex disk drive. Featuring its own Z80A processor with external ROM and RAM, the Timex drive treats the Spectrum as a terminal. By changing the interface unit, the system could be connected to any other type of computer — indeed work is in progress at Timex Towers on a Commodore 64 interface right now. Theoretically at least, this means that a change of computer needn’t mean making your Timex drive redundant.

The Timex disk system has been designed so that it does not require a single byte of the Spectrum’s own RAM memory, and as a result it simply can’t interfere with any commercial software. Unfortunately, however, RAM ‘photography’, using a hardware interrupt switch (similar to the BETA PLUS system) is not catered for. The Timex Operating System (TOS) is the only Spectrum based operating system to include a complete tree-structure directory facility similar to professional systems such as MS-DOS or CP/M. This enables the user to maintain a tidy household containing all the disk files. Other good features are the excellent random and sequential file handling, and the pair of serial communication ports (RS232C) which are fully software supported.


As is usual (and perhaps, inevitable) several errors have crept in during the Fast Storage Series. The worst of the lot was in last issue, with the statement that the OPUS drive has the same format as Amstrad and Tatung — which it doesn’t. The timings given for the OPUS drive proved to be wrong: Cataloguing happens in a split second and loading a screen takes approx. 5 seconds not 4.

Dimitri Koveos from Abbeydale Design Ltd, designers of the K-DOS, has cleared up several errors in our Kempston drive review, notably to do with the speed of the drive. The review stated that the drive had a slow access time. As indicated in our comparison table, this is not so — in fact, owing to the clever coding, K-DOS is the fastest system for the Spectrum and apologies are deserved to both Kempston and Abbeydale Design. Sorry. Also, no mention was made of the CLEAR 0 function, which compresses BASIC programs to save memory.

Furthermore, Dimitri reckons the command structure is no more difficult and tedious than the microdrive/wafadrive commands — a point one can argue about ad infinitum.

Running the operating system outside BASIC, BETA PLUS can have very short and simple commands for regular file access and only runs into problems when disk access is required within BASIC, where PRINT USR statements are used for link up.

Further corrections should be sent to the department of errors, Crash towers...



Hardware abounds with no less than four separately enclosed units. The three main units, consisting of the 3 inch disk drive, the controller and the power supply, are fitted in three identical enclosures. The small interface unit plugs into the expansion bus of the Spectrum. Connection to the controller is via a hefty coiled cable and D-plug. Up to four drives may be linked to the system, but drives 3 and 4 necessitate an extra power supply. The controller features two serial ports which require special cables with edge connector sockets. The controller also features a system reset button and power LED, while a reset switch on the interface provides a Spectrum only reset. The interface does not feature an expansion port and if the ZX printer or ALPHACOM 32 printer is to be connected, a T extension connector will be required.


Unlike all other disk units in this series, the Timex disk system is a complete computer with its own Z80A processor. This system treats the Spectrum as a terminal only and the interface passes commands and data onto the controller. The Timex Operating System (TOS) is configured as an extended Sinclair BASIC and resides in a shadow ROM. It has 1 kbyte of external RAM at its disposal for storing the drive characteristics, buffers and variables. These must initially be booted up from any pre-formatted disk.

The BASIC Extension instructions can either be executed directly from the keyboard or from within the program like any other BASIC instruction. The TOS commands may also be accessed directly from machine code by selecting the external ROM with a jump to address 0008H. In the external ROM there is a routine to call routines in the BASIC ROM, so that all BASIC functions may be accessed at any time. Calling 0603H or 0604H reselects the BASIC ROM.

TOS supports a subdirectory ‘tree-structure’. There is a root directory which may contain other directories. Directories can be nested and the specific route from the file to the current directory is called a pathname. Any Filename extensions such as for example .BAS and .COD may be used to separate the different file types, although only .DIR (for directory names) and .SCP (for communication channel names) have a specific meaning to TOS.

File names may contain ‘masks’ or ‘jokers’. The plus sign can be used to replace all or several characters in a name field, while the question mark replaces one character only. File names with masks (templates) can be used with most instructions and provide access to a group or batch of files.

TOS supports random access and sequential files. A data file must be opened and a channel for input or output linked to it. INPUT* and PRINT* are the only instructions that allow access to a specific part of a file. When the OPEN #* instruction is executed, the file structure is defined. The file can either be a stream file with no record structure, where you can read or write a variable number of characters up to 256, or a record file with a fixed record length of a specified amount of characters. Stream files can only be read sequentially or in random fashion with an AT command.

TOS provides up to 16 channels. Channels 1 to 4 are fast (each have an dedicated 512 byte buffer) and 5 to 16 are slow (common 512 byte buffer). The floppy disk controller is equipped with two RS232C serial communication ports (SCP’s). These have to be set to the correct format and baud rate by configuring the two dedicated SCP files with a FORMAT* statement. The files may then be opened in a similar way to the stream or record files for sending or receiving data.


TOS (Timex Operating System) configured as a BASIC Extension.


CAT* displays the disk directory contents. The list displays the name, the file type (extension), the file size in bytes, the disk allocation (sectors occupied) and two columns indicating whether the file is write-protected (by means of the TOS software facility, not the write-protect tab). The only two extensions that have special meaning for TOS are .DIR indicating a subdirectory and .SCP a communication channel.

FORMAT* "drivename" TO "diskname" formats a disk in the requested drive. TOS is copied onto each disk (requiring 16K) for booting up. The directory requires 4K. TOS requests confirmation before proceeding with the formatting.

SAVE* pathname LOAD OPTIONS saves a file to disk. The pathname consists of the subdirectory (or subdirectories) and a filename. The LOAD OPTION may be LINE number for BASIC autorun, SCREEN$ for a screen file, CODE start, length for a machine code file and DATA arrayname () for a numeric or string array. If an existing file is specified, TOS displays a warning with a prompt to overwrite the existing file (unless the save syntax includes an overwrite enable). If the program saved is called "START" with a linenumber for autorun, TOS will autoboot from a reset if the disk is in drive A.

LOAD* pathname LOAD OPTION loads a file from disk.

MERGE* pathname merges a BASIC file from disk with the existing program and variables in the Spectrum memory.

DIM* pathname creates a 0 size file or an empty directory. The use of the path means that files can be created outside the current directory. For a directory, a filename with a .DIR extension must be used.

GOTO* pathname or GOTO* "drivename" d changes the current directory/disk. Special pathnames exist for moving up or down the directory hierarchy. GOTO* "↑↑ ..." moves up one or more nested directories and GOTO* ":" goes to the Root directory.

LIST* displays the current directory location (pathname of source directory, its level and the drive). TOS allows the change of the current directory to another drive without knowing the disk name with a GOTO* "drive name" d.

GO SUB* (pathname) or GO SUB* "drive name" d changes the current directory/drive and stores the return directory/drive on a directory/drive stack ready to be recalled with a DRAW* command. This is very useful for applications requesting a change of directory/disk to perform a task with subsequent return (using DRAW*) to the source directory/disk. TOS allows up to 8 levels of nesting.

DRAW* pops the source directory/disk. Used in conjunction with the GO SUB* command.

ATTR* pathname P, U, I or V write/erase protects, unprotects, hides (I) or unveils (V) files or directories. The pathname can be a template, so more than one file can be affected. A FORMAT* instruction can still destroy a protected disk.

MOVE* source-pathname TO destination-pathname copies a file or SCP to another file or SCP. The source is not destroyed or modified.

ERASE* pathname (N) erases files. TOS will ask for confirmation. The instruction will generate an error report if the file is write protected or belongs to a tab-protected disk.

LET* old pathname TO new pathname renames a file, directory or SCP.

FORMAT* SCP-pathname changes the configuration of the SCP. The parameters are text or bytes, autolinefeed on or off, software protocol, input with wait, baud rate, parity, and number of stop-bits and databits.

OPEN #* expression 1; pathname, mode (expression 2) opens a file or SCP and associates a channel with it for access through PRINT* and INPUT* statements.

PRINT* #n; STR (;AT P) writes characters or records to a file or SCP via a channel. Maximum record number is 65535.

INPUT* #n; VAR (;AT P) reads a character or record from a file or SCP via a channel.

CLOSE #* expression closes the open file linked to the channel number given by the expression.

LIST*# (channel number) lists information of all or specified channel numbers. The information includes the channel number, the channel type (fast or slow), mode (input, output, random, append), type (record or stream), current record (file pointer position), size (file size in bytes) and number of free channels, or if it’s an SCP: mode, type, record length (1 if stream), baud rate (50 to 19200), data type (text or bytes), autolinefeed, XON or XOFF and number of free channels.


46 error reports, extensive and detailed.


Two serial communication ports (SCP’S), baud rate adjustable from 50 to 19200 baud. Utility program provided on disk for operation of LPRINT and LLIST commands through serial port A.


Excellent manual providing startup and introduction to new disk drive users followed by detailed description of TOS system and commands, directories and pathnames, random and sequential file handling and serial ports application with example programs. Appendix with TOS command summary, error reports, description of utility programs and RS232C connection details. Guidance is provided for the programmer wishing to operate from machine code (detailed list of TOS routines together with their call addresses) and for error trapping control.


None, but selection of utility programs on disk including BACKUP (copies an entire disk), LOSYS (updates the TOS on existing disks without losing any data on the disk), DUMP (displays selected file on screen in hexadecimal and ASCII notation) and LPRINT (provides LPRINT and LLIST commands for 80 column printers connected to the serial port A).


No Centronics parallel port for low-cost 80 column printers available.
Extensive amount of hardware cluttering the desk.


Excellent TOS with directory filing structure, random and sequential data file handling and full SCP software support.

TOS operates as BASIC extension with very short and uncomplicated commands (unlike microdrive commands) and easy access from machine code is possible through well documented call addresses.

TOS does not use a single byte of the Spectrum RAM.


3.0 inch hard cased disks in double density format. Price of media starting from £2.70.


Number of drives supported per system: 4
Storage capacity: 160K per side
Sector size: 1024 bytes


Formatting: approx. 31sec
Cataloguing: approx. 3.5sec
Loading a screen: approx. 5.5sec


A table of all the tested drives concludes the series on fast storage media, and provides a basis for direct comparison of all the different systems available to the Spectrum owner. The various features listed enable any future disk or cartridge drive owner to make up his or her mind as to which drive is particularly suited for the required application.

Before delving into the comparison chart, it would be wise to clearly define what the system is going to be used for. At present it would appear that there is a total lack of application programs to support the disk based systems, and the drives may be regarded as purely tools for BASIC and machine code programmers. Disk drive producers should be made aware of the fact that a very large proportion of Spectrum owners are not dedicated programmers, but are more avid consumers of commercially available software, be it games software or wordprocessing and database packages.

Some effort on the part of drive manufacturers expended in providing application programs for their system could result in an opening up of what is at the moment still a fringe market...

ZX Interface 1 stacks under the Spectrum and includes the Microdrive interface, RS232C serial interface, local area network and expansion port. Microdrive plugs in via short flat cable and has extension connector for further drives.
Extended BASIC residing in shadow ROM, which gives access to the drive and provides software support for the serial interface and local area network.
Average access time with long search periods
Microdrive cartridges with over 85K formatted capacity
Although the support has not reached the expected level, it is still the most widely supported fast storage media tested
  • Software supported serial interface
  • Local area network links up to 64 stations for multiplayer games or school environments
  • Still the cheapest fast storage device
  • disappointingly slow performance for a fast storage device
  • Some users complain of the short cartridge life due to tape roller pinching
£99.90 inc.
Large cream coloured 2.8 inch disk drive connected to black Spectrum interface unit with expansion port.
Extended BASIC residing in shadow ROM
Fast Access (never longer than 8 sec)
Unusual 2.8 inch hard-cased disk with up to 100kbytes capacity (both sides)
No drive specific programs available yet, but utility included for transferring files from tape to disk
  • Fast formatting
  • probably more reliable media and faster than Microdrive and wafadrive
  • rare disk format may cause supply problems
£119.00 inc.
Interface for Shugart compatible drives in single and double density format. Magic button for storing complete RAM memory to disk. Interface includes expansion port.
TR DOS V4 commands are accessed in operating system environment but can be called from BASIC with PRINT USR and REM statements. DOS resides in ROM and caters for 35, 40 and 80 track drives
Fast access times
depends on drives installed, 3 inch, 3,5 inch and 5.25 single and double density up to 640K capacity
Very little support from software houses. Magic Button provides back up facilities for games and utilities
  • Excellent RAM image saver
  • Sequential and random datafile access
  • Short commands in DOS environment
  • Utility disk for tape copying and filing work
  • requires only the printer buffer area of the Spectrum RAM
  • needs more support from software houses
£109.25 inc. plus £4 P&P
Complete system including two stringy floppy drives and serial and parallel ports
Extended BASIC residing in shadow ROM with commands similar to ZX interface 1
Variably slow depending on tape length of cartridge. Compares to Microdrive spec.
Spectral Writer by Softek included in package. Small library of games and utilities available.
  • Software supported Centronics and serial interface
  • Standard unit includes two drives
  • Wafadrive Operating System not apparent until initialised
  • Wildcard facility
  • Wafadrive is faster than cassette, but a lot slower than floppy disk media
  • Fairly expensive media
  • Requires more support from software houses
£129.95 inc.
Complete disk drive system with 3.5 inch drive, Kempston joystick interface, Centronics parallel port, mono video output and expansion port
Extended BASIC. Syntax compatible with Microdrive commands. Supports data storage with serial and random access files. Fast RAM disk operation for fast file handing
Fast access time
3.5 inch singlesided single density providing 180K capacity
Games, word-processing and database packages available in OPUS format
  • Sequential and random access files
  • RAM disk option
  • Autoboot facility
  • Software supported Centronics interface
  • Several add-ons integrated in one unit including joystick interface and monochrome video output
  • can be expanded to twin drive unit with integral second disk
  • Requires more support from software houses
  • PRICE:
    £199.95 inc. VAT
    Interface for Shugart compatible double density drives. System reset switch
    ROM based Kempston Operating System developed by the same company as Watford Micro’s SP-DOS (Abbeydale Design Ltd). K-DOS is accessible through BASIC using PRINT 4: command: PRINT variables statements. Provision for 35, 40 and 80 track formatting
    Very fast access times due to careful machine coding and variable track access delays to accommodate the faster drives. K-DOS can access a complete track in one revolution (no skewing) averaging 15Kbytes/sec. Proves to be the fastest DOS tested
    Depends on the drives installed, 3 inch, 3.5 inch and 5.25 double density with up to 820K formatted capacity
    Tasword 2, Omnicalc 2, Masterfile, OCP editor/assembler, OCP address/stock/finance manager, Word Manager, Extended Art Studio can be configured to run with K-DOS
    • BASIC overlay facility
    • Autoboot option
    • BASIC compression routine
    • Error trapping function (ON ERROR GOTO...)
    • Wildcard facility on CAT. ERASE and MOVE for batch file handling
    • Selectable track access timing
    • No expansion port
    • No random record file access
    £85 inc VAT
    Four units incorporating the Spectrum interface, controller, power supply and 3.0 inch disk drive. The controller is an independent Z80A processor system with disk interface and two serial ports.
    Timex Operating System configured as an extended Sinclair BASIC, residing in ROM. Supports drive functions and the two serial communication ports.
    Fast access times
    3.0 inch hardcased with 320K formatted capacity per disk (2 sides).
    Very few, very little support from software houses.
    • Efficient command structure within BASIC
    • Excellent directory structure facility
    • Sequential and random access of datafiles
    • Doesn’t require a single byte of the Spectrum RAM
    • Extensive amount of hardware
    approx. £260