w_smith@wookie.DEC.COM (Willie Smith, LTN Components Eng.) (06/26/87)
JEllsworth@HI-MULTICS.ARPA was looking for a hard disk or RAM disk for an S-100 machine. A few ideas, taken from my present configuration and my current wish list: 1) Compupro (Viasyn) DISK-3 hard disk controller. This will talk to any mix of ST-506 drives, does 24 bit DMA of any number of sectors, can work in track/ sector or absolute sector number mode, and has local intelligence (8085?) to take care of all the messy details for you. You set up a 16 byte I/O Parameter Block in memory and kick the DISK-3. It reads it into internal memory, does the requested function (complete with seeks, head settles, etc), and gives you back (in the IOPB) a completion status. Writing the software drivers in Z-80 assembly was very simple, and I have yet to have a problem with the board. I'm running with 2 ST-225 drives, which seem to work well, in an Integrand disk box, which is very well built and (I suspect) bulletproof.... 2) Macrotech 512K VRAM board. This is kind of expensive for a RAM disk, but it provides real memory access _and_ RAM disk simultaneously. I'm using part of the additional memory for BIOS extensions, I just load up my registers with the important variables, swap banks, and have more than enough room to play. It's nice having 64K free for your BIOS.... :+) The one thing that bugs me about the VRAM is that while the memory section is real fast (they do some handwaving to say it's 12 nS, but the chips are 120 nS), the RAM disk ports need 2 I/O wait states with a 6 to 8 MHz Z-80. Digital Research Computers LS-II(?). Not to be confused with the software company of the same name, you can find them in the back of BYTE. The Light Speed II is a 1 Meg version of their LS-I (256K), which I played with last weekend and was very impressed with. These are really quite inexpensive, and should work well if you are just looking for straight RAM disk, and can handle a little kit assembly. A little side note: with the DISK-3 and the VRAM board, you can fairly easily whip up a hard disk cache. You get to the sectors that are in the cache thru the RAM disk ports, and the DISK-3 does DMA to the memory side. This does not work with the LS-II or other 'pure' RAM disks. Just on the off chance that you end up with this configuration (or see below), drop me a line and I'll see about sending you the drivers. In some simple benchmarks of 'real world' applications, running a RAM disk made things go 4 times as fast, while the cache was 'only' twice as fast, but the cache doesn't give 'DISK FULL' errors when it fills up.... 3) Macrotech ADIT board with external RAM boards. The ADIT board can substitute for the RAM disk ports on the VRAM board if you have memory in other banks that you are not using. It will do DMA between banks, and also has virtual RAM disk ports that will keep track of everything for you. You also get from 4 to 16 I/O ports and a 6 MHz Z80 and 16 or 32K of RAM and a little tiny multitasking 'operating system' in an EPROM that runs everything for you! I've ordered one cuz I need some more serial ports, but I suspect I'll be adding a couple of meg of memory boards for a RAM disk and rewriting my cache software to take advantage of the ADIT instead of the VRAM. Wanna buy a VRAM board? :+) Hope this helps, any questions, feel free to send mail. Willie Smith w_smith@wookie.dec.com w_smith%wookie.dec.com@decwrl.dec.com
apn@nonvon.UUCP (root) (06/27/87)
in article <8706260653.AA17157@decwrl.dec.com>, w_smith@wookie.DEC.COM (Willie Smith, LTN Components Eng.) says: > > JEllsworth@HI-MULTICS.ARPA was looking for a hard disk or RAM disk for an > S-100 machine. A few ideas, taken from my present configuration and my > current wish list: > > 1) Compupro (Viasyn) DISK-3 hard disk controller. This will talk to any mix of > ST-506 drives, does 24 bit DMA of any number of sectors, can work in track/ > sector or absolute sector number mode, and has local intelligence (8085?) to > take care of all the messy details for you. You set up a 16 byte I/O Parameter > Block in memory and kick the DISK-3. It reads it into internal memory, does > the requested function (complete with seeks, head settles, etc), and gives you > back (in the IOPB) a completion status. Writing the software drivers in Z-80 > assembly was very simple, and I have yet to have a problem with the board. I'm > running with 2 ST-225 drives, which seem to work well, in an Integrand disk box, > which is very well built and (I suspect) bulletproof.... > > 2) Macrotech 512K VRAM board. This is kind of expensive for a RAM disk, > but it provides real memory access _and_ RAM disk simultaneously. I'm using > part of the additional memory for BIOS extensions, I just load up my registers > with the important variables, swap banks, and have more than enough room to > play. It's nice having 64K free for your BIOS.... :+) The one thing that bugs Thought I'd throw in my 0.02$ ... there is a disk controller card that has a hard disk 8" All known soft-sector cpm formats 5" All known soft-sector cpm formats and DMA ram disk all on one card!! track buffering is implemented to provide very fast floppy i/o. DMA will work in multimaster mode in 16bits. 5mhz 8085 on board. Source is given out with purchase of the board for some small anount more. Works upto 12mhz .. This is available from fulcrum computer products -- 707 433 0202 They also make super fast 256k / 1M static cards with the battery backup on board... makes for a great ramdisk. NO NEED TO COPY STUFF OVER ON POWER UP!! alex novickis UUCP: {ihnp4,ames,qantel,sun,seismo,amdahl,lll-crg,pyramid}!ptsfa!nonvon!apn {* Only those who attempt the absurd ... will achieve the impossible *} {* I think... I think it's in my basement... Let me go upstairs and check. *} {* -escher *} -- UUCP: {ihnp4,ames,qantel,sun,seismo,amdahl,lll-crg,pyramid}!ptsfa!nonvon!apn {* Only those who attempt the absurd ... will achieve the impossible *} {* I think... I think it's in my basement... Let me go upstairs and check. *} {* -escher *}