Wow, the "killer POKE" works! (Commodore PET 2001-8)

On Sun, Jan 25, 2004 at 05:46:54PM -0800, steven wrote: my increase! That's because it's a 2001-8. The old, TTL video PETs used that POKE to, in effect, let BASIC "ignore" the vertical blanking interrupt. In essence, the ROM routing for PRINT checks the VBI and only fiddles with video memory when the beam is off. That's why directly manipulating screen memory in machine language was always faster. The problem came with _later_ models than yours. IIRC, the effect of the "killer poke" was to change the direction of a bit in a PIA or VIA from an input bit to an output bit. The consequence of that is, with one of the later models with a different video circuit, a totem-pole transistor arrangement was permanently engaged and one of the transistors was overdriven and smoked. -ethan -- Ethan Dicks, A-130-S Current South Pole Weather at 26-Jan-2004 08:20 Z South Pole Station PSC 468 Box 400 Temp -19.5 F (-28.6 C) Windchill -45.5 F (-43.1 C) APO AP 96598 Wind 8.69 kts Grid 066 Barometer 688.9 mb (10293. ft) Ethan.Dicks(a)amanda.spole.gov