Posts by Richard Zealley
Hewlett Packard HP 95LX
The HP 95LX was launched on April 23, 1991 before the term personal digital assistant, or PDA, found its way into everyday use putting the power of a computer into the palm of your hand. It ran MS-DOS v3.22 in 512K bytes of RAM and 1M-byte ROM and had a QWERTY keyboard and a separate…
Read MoreApple Pascal Disks
Information about the contents and use of Apple Pascal disks with Apple II computers including how to manage boot disks.
Read MoreApple Pascal on Apple IIe
Back In August I took delivery of a boxed Apple IIe in excellent working condition. I had used an earlier Apple II at university in 1982/83 to learn Pascal and hoped to find a set of Pascal diskettes which I duly did a couple of weeks later. I didn’t want to try and do too…
Read MorePsion Series 3mx Disassembly
A complete guide to disassembling a Psion 3mx and identifying where this can go horribly wrong based this on a recent example which I’d bought as spares/repair from eBay
Read MoreSinclair ZX Spectrum 48K
The much anticipated successor to the ZX81, the ZX Spectrum was originally released with options for 16K or 48K RAM. The 16K Spectrums were upgradable to 48K. It was recognisable by its distinctive rubber key keyboard and it sported rainbow stripes to indicate the introduction of colour, where the ZX80 and ZX81 were purely monochrome.
Read MoreSinclair ZX81
The ZX81 was the successor to the ZX80, still based on the Zilog Z80A but with 8K ROM rather than 4K, and the same 1K RAM. The biggest technical difference was the integration of many of the ICs into one component, which reduced the chip count and the cost, starting at £49.95 for a kit, and £69.95 for a ready-built machine.
Read MorePsion Series 3mx
The Psion Series 3mx was the last model in the Series 3 line, launched in mid 1998, and is an upgrad to the Series 3c. The main differences are: a silver metallic finish, a CR2025 backup battery, and a faster processor, the 16 bit NEC V30MX (80C86 compatible) running at 27.684 MHz. It has a backlight like the later models of the Series 3c.
Read MorePsion Series 3c
The Psion Series 3c followed on from the Psion Series 3a and predating the Series 3mx. The main differences are: a redigned case in black with a rubberised coating (that degarded into a sticky mess over time), an infrared port, and a backlight (on later models).
Read MorePsion Series 3 Software
My collection of Psion Series 3 software on SSD.
Read MoreTowers of Hanoi for Sinclair ZX81 in 1K
My one claim to fame – a short program I submitted to Sinclair Programs magazine in 1983. I was shuffed with this because I’d managed to cram it into just 1K. I hadn’t yet invested in a 16K RAM pack.
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