Specifications
The table below shows the specifications of Colin MKI, representing the state of play for most
of his life.
| Processor | Z80A - 4Mhz |
| Memory | 64kB Static RAM |
| Firmware | BOS V2.3 - (2k EPROM)* |
| Operating system | CP/M 2.2 |
| Video display | Memory mapped colour Teletext display - 40 chars x 24 lines - UHF output (PAL), Composite video & TTL RGB + Sync |
| Keyboard | 7 Bit parallel ASCII - Carter Professional Model 756 |
| Floppy Disk storage | Dual 8" Floppy drives. SSSD - 77 track (Shugart 801) Single 5 1/4" Floppy drive. DSDD - 40 track (Micro Peripherals) |
| Cassette storage | Dual cassette interface - Max 2400 baud (CUTS) |
| Printer output | RS232 & 20mA interfaces |
| Serial interfaces | Dual channel RS232 ports with full handshaking |
| Audio interfaces | Dual sound processors - (AY-3-8910) Speech synthesis processor - (SPO256-AL2) |
* In the early stages, the firmware was called 'CSYS/80'. According to the Custom 80 manual, it should be pronounced 'sea-siss'. This was the original firmware that was supplied with the keyboard interface card. It consisted of two parts; CSYS/80, which was the operating system for the computer that provided all the basic input / output functions taking up 1.5k of the EPROM, and INSECT, which was a debug / execution program that lived in the remining 0.5k. As supplied, my original firmware was serial number 1303. (CSYS/80 V1.05. INSECT V0.09)
Once I got into improving and extending the basic system as described in earlier pages, I modified the firmware and renamed it BOS. (Basic Operating System).
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