The TOS V A.2 Demo Disk is the demonstration disk Timex Computer of Portugal supplied with its FDD disk drives and the TOS (Timex Operating System) that runs them. The disk is organised in TOS folders: MATHS (linear regression, a random number generator and a quadratic equation solver), FUN (a calendar, a colour bar display and, in FUN/GAMES, a dice game and a number-guessing game), UTIL (disk backup, screen dump, printer and RS232 utilities) and FILING (a random-access address file demo). A help program lists every TOS command with its syntax and a description.
Two editions survive, both with the volume name DEMO: one labelled for the TC 2068 and one for the Spectrum. The maths and fun programs are identical on both; the Spectrum edition has its own versions of the help program and of the backup, system-load, dump and printer utilities. In the United States Zebra Systems sold the drives for the Timex/Sinclair 2068, which used them in Spectrum mode through Zebra’s adapter.
The download
- Seven tape conversions of the plain BASIC programs: Calendar, Colours, Dice, Hi-Lo, Linear Regression, Quadratic Equations and Random Numbers. They contain no disk commands and are unchanged from the disk.
TOS command reference.txt: the help program’s screens rendered as text. It covers ATTR *, CAT *, CLOSE #*, MOVE *, DIM *, ERASE *, FORMAT *, GO SUB *, GO TO *, INPUT *#, LIST *, LOAD *, MERGE *, LET *, OPEN #*, PRINT *#, RESTORE *, DRAW *, SAVE * and NEXT *, including pathnames, templates, the directory stack, file protection and the serial channels (SCPs).- Disk images of both editions and of the Timex Portugal “BARCODE” disk, for the FUSE emulator with the FDD3000 interface (fdd3000e).
- Every file of both editions as a TAP, in the disk’s folder layout. The UTIL and FILING programs use TOS commands and the drive’s RS232 channels, so they need the disk system.
- The Bar Code Reader demo from the BARCODE disk (Spectrum): a BASIC menu and a driver at 65300 for a Timex Portugal bar code reader, supporting UPC/EAN/JAN/WPC, CODABAR, CODE 39 and 2 of 5. It needs the reader hardware.
- Diskread, a TOS file information utility found on another copy of the demo disk. Its REMs credit Chuck Dawson, with output format changes by D. Franson dated 2/27/87. It opens a file as a TOS channel and reads its header to show the file type, autostart line, lengths and start address.
Program Analysis
The TOS command syntax
TOS adds its commands to Sinclair BASIC by following ordinary keywords with an asterisk: LOAD *"pathname", CAT *, OPEN #*1;"file";r;100, PRINT *#1;r$;AT n. Pathnames use colons as separators, as in ":demo:filing:address.rec" in the address demo, and files and directories are created with DIM *. The address demo opens a random-access file of 100-byte records and reads or writes a record by number.
The demo programs
Calendar draws a month grid with PLOT and DRAW after asking for the month and year, and can also count the days between two dates or give the day of the week. Linear Regression collects points, computes the least-squares slope and intercept and plots the points as small circles with the fitted line. Dice redefines a UDG as a pip and rolls five dice, letting you hold dice between throws. Colours fills the screen with the eight PAPER colours at normal and bright levels.
Notable Techniques
- Calendar uses a day-number formula with century corrections and works out the weekday as the remainder after dividing by 7.
- Dice marks the die being chosen by POKEing a FLASH attribute directly into the attribute file.
Potential Issues
- Calendar’s month string reads
SetandOcbfor September and October. - Linear Regression prints the intercept as a tiny floating-point remainder (such as 5.96E-9) when the true value is zero.
The seven tape programs were tested in ZEsarUX on a stock TS2068. Programs that use TOS commands were not tested, because ZEsarUX has no FDD emulation.
Image Gallery
Note: Type-in program listings on this website use ZMAKEBAS notation for graphics characters.