Started by jamesots, 00:21, 04 November 17
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Quote from: Zoe Robinson on 14:16, 04 November 17FID drivers? As in the SD card is being accessed like a giant floppy disk? That's pretty sweet on its own. Could that be ported to the CPC?
Quote from: GeoffB17 on 16:42, 04 November 17Just now, my PCW (still the same machine I got new back in 1983) is quite happy with JonB's uIDE drive. OK, that provides 13 @ 8 Mb drives, and your setup would provide lots more, but the present setup provides WAY MORE than enough for my needs. Anyway, how efficiently could the PCW, and CP/M, cope with 16 Mb drives regarding directory entries, block sizes, dir searching, etc? I'd wonder if the 8 Mb drives are already near the practical limit?
Quote from: GeoffB17 on 16:42, 04 November 17The AY chip sounds interesting, but I've seen dubious comments about that. All relative of course! I've got an old PC with a SB clone in, that has an AY chip. I was asking elsewhere if it was worth trying to do much with the AY, given that I've got a Roland LAPC-I card in a different old PC. I was told that the Roland is so much better than the AY that it wasn't worth the bother. So, this leads on......
Quote from: HAL 6128 on 22:36, 04 November 17I think not. That's what JonB tried to develop together with his uIDE hardware. It seems that the CPC CP/M+ version (which is different and older from the PCWs ones) are not capable of working with FI-Drivers. Instead the CP/M itself (C11CPM3.EMS) should be compiled with a new drivers integrated.
Quote from: jamesots on 00:21, 04 November 17So far I've added an AY sound chip and joystick port, composite video output, 512Kb of extra RAM, 32Kb of ROM and an SD Card. The SD Card uses its own FID drivers, rather than emulating a floppy drive like the HxC things. The PCW can boot from the ROM, which in turn loads CP/M off the SD card.
Quote from: jamesots on 23:50, 04 November 17It seems to be ok with 16 Mb drives, although I can only fit 4 drives into memory rather than 13. I could probably get 8 drives if I increased the block size to 4096. I'm not sure I need that many drives though. Also, I only have 512 directory entries on my 'massive' drives, so I'll probably run out of directory space before I run out of disk space. It's all swings and roundabouts when trying to decide on all the drive parameters, and since I expect I can fit all PCW software ever written on one 2Gb SD card, it probably doesn't really matter which way I go
; Block size = 4096 bytesdpb: dw 128 ;SPT - sectors per track db 5 ;BSH - block shift factor db 31 ;BLM - block mask db 1 ;EXM - Extent mask dw 2039 ;DSM - Storage size (blocks - 1) dw 511 ;DRM - Number of directory entries - 1 db 240 ;AL0 - 1 bit set per directory block db 0 ;AL1 - " dw 8000h;CKS - DIR check vector size 8000=CP/M 3 fixed disk dw 1 ;OFF - Reserved tracks (for warm booting) db 2 ;PSH - Phys sector shift (2 => 512 byte sectors) db 3 ;PSM - Phys sector mask (3 => 512 byte sectors)
Quote from: JonB on 11:47, 05 November 17The problem with a single huge drive, apart from directory entries, is that you only have 16 CP/M user areas in which to organise your files, so you will soon end up with enormous DIR listings on all of them. I think that is one reason to stick with smaller partitions but have more of them. The other problem which you will come across is performance. I noted file and directory accesses were getting slower as I added more files. It becomes quite noticeable after a while.
Quote from: JonB on 11:47, 05 November 17The uIDE FID gives you 13 possible drives (c: - p: with m: still a RAMDISK) having 8MB and 512 directory entries each. I thought the practical limit on CP/M drive size was 8MB per, but I see you have done better. Nice one!
Quote from: JonB on 11:47, 05 November 17As you can see, I reserved a track for a boot sector... [/font]
Quote from: JonB on 11:47, 05 November 17The driver also has a map built into it. This is so that you can switch logical drives in / out at will, although the feature isn't implemented yet because I'm not sure how to access the map structure as held in the FID's memory and the PCW seems to cope fine as-is.
Quote from: jamesots on 00:21, 04 November 17So far I've added an AY sound chip and joystick port, composite video output, 512Kb of extra RAM, 32Kb of ROM and an SD Card.
Quote from: Prodatron on 02:38, 06 November 17Sounds really cool! I need that for the SymAmp player (AY sound), controlling my mouse pointer (Joystick), and FAT 16/32 access...Is it possible to access the 512byte sectors of the SD card directly (low level sector read/write)?
Quote from: JonB on 16:29, 06 November 17Hope you saw my PM. Would you be prepared to share details of your design with me? I would like to get my uIDE cards to boot without accessing the floppy drive, but I think I will need a bit of help..
Quote from: JonB on 14:09, 07 November 17I probably need: Schematics of your interface (so I can recreate it with uIDE compatibility).Details of the mechanism by which it detects the end of the first level boot - port addresses, ROM disassembly, etc.Source code of the second level boot (the code you put in the SD card's boot track).CPLD programming details (I assume you're using some programmable logic).Your patched EMS file.Probably some advice on build tool chains you are using (I use TASM for Z80 assembly) especially for the programmable logic.Basically, everything required to boot the PCW from a mass storage device.. I would substitute your SD card boot code for IDE code (same thing functionally - read boot code off the first track).
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