Failures

Things which don't work, and may never work, and why :-

• CP/M programs which directly do low level disk configuration or disk I/O, directly to the hardware itself, such as FORMAT.COM, FRMSDX.COM, SIDFMT.COM (ie: FORMAT.COM renamed), RCHECK.COM and FDXB.COM.
• Programs which do direct access to the cassette tape ports, will never be able to use virtual cassette tape, such as certain games loaders. They will of course attempt to use real cassette tape.
• REMEMOrizer is incompatible with the NODE ROM. This is because the SDX support uses memory normally used by the NODE ROM for SD Card and RAM Disc variables and buffers.
• REMEMOrizer is incompatible with the FDX, HDX or HRX, in exactly the same way that an SDX is incompatible with them.
• REMEMOrizer is incompatible with the combined 80 column and RS232 card, because REMEMOrizer also provides the 80 column card function. If you have one of these cards, odds are you have the SDX to go with it anyway.
• Iain observes that REMEMOrizers 80 column VGA output isn't acceptable to his TV (which supports VGA input). The pixel clock used for REMEMOrizers VGA output is 1.7% off - perhaps the TV is (legitimately) fussier than most.
• Jon only gets 20 out of 24 lines on his 80 column output. He is using an "Advent" monitor. Reason unknown.
• The Speculator hardware and REZSPEC software is carefully timed to work on UK 50Hz PAL TV, so don't expect it to work on US 60Hz NTSC. There isn't really enough vertical blank period at 60Hz to make copying from Spectrum screen memory to VDP viable.