mvk@aix01.aix.rpi.edu (Michael V. Kent) (04/16/91)
I've just ordered the OctoRAM memory expansion card for the IIGS from Digital
Data Express. My conversation with the saleswoman raised a few questions in
my mind about DMA, but I bought one anyway.
1) I know that only the first 4 banks of SIMMs on the card are DMA compatible,
but the saleswoman stated that the card would be inoperable if more than 4
SIMMs were installed with an Apple DMA SCSI. Since I have such a beast, I
am wondering -- is this true?
2) I was also told that the RAMFast SCSI controller would work with all 8
SIMMs, but only 4 would be DMA (which is what I expected). What does RAMFast
do that Apple doesn't?
3) What's the current price of a RAMFast, and what does the ROM 2.0 upgrade
do for me if I buy one? I currently have a Chinook CT100 and plan to add a
ZIP GS, if that matters.
4) Can my Apple DMA SCSI go in slot 3 without disabling anything important?
I'm kind of running out of slots. My system:
Apple IIGS ROM 01
slot 0 - Apple 1 Meg card (soon to be OctoRAM)
1 - ImageWriter Iwc (Super Serial card)
2 - 19.2 kbaud modem (modem port)
3 - empty
4 - SuperSonic stereo / digitizng card
5 - Apple Drive 3.5 (SmartPort)
6 - Apple Disk ][ (Disk ][ controller card)
7 - Apple DMA SCSI card
HyperStudio digitizing card connected to A/D converter
I've got a LocalTalk connected to the printer port.
AppleTalk is currently inactive (I'm trying to activate it, but I'm not sure
what slot to move my SCSI card to).
Any ideas?
Mike
--
Michael Kent mvk@itsgw.rpi.edu
McDonnell Douglas Rensselaer Polytechnic Institute
St. Louis, Missouri Troy, New York
Apple II Forever!joseph@rutgers.rutgers.edu (Seymour Joseph) (04/17/91)
Mike, I have AppleTalk enabled (for printing to an AppleTalk Imagewriter I share with my wife's Mac) so I keep my RamFast SCSI card in slot 1. I bought my RamFast SCSI card from TMS Peripherals. They advertise in the back of A+/Incider. I think I paid $179. The 2.0 ROMS are an option and cost about $15 more. The version 2.0 Roms for the RamFAST SCSI card include a mouse based disk management program and support for removable devices such as CD-Roms, Syquest cartridge hard disks, and even tape backup devices. The included utility program even allows the RamFAST to backup a disk partition(or partitions) to tape IN THE BACKGROUND while you are using your GS for something else. The dialog between the hard disk and the tape drive occurs completely in the RamFAST card, your Apple IIGS is free to do other things during the backup.(GS/OS thinks that the partitions being backed up are write protected during the backup process so you cannot change them while they are being copied to tape.) I also have an OctoRAM card. I have 2-1MB parts in it and have no problem running with my RamFAST with DMA enabled and my TWGS. My understanding is that no matter how many slots for ram your card has, the Apple IIGS will only do DMA to the first 4 rows (SIMMs) for a maximum of 4 meg. If you use 256k parts in the Octoram, that means that only the 1st Meg would be DMA (not good) If you use 1MB parts, only the 1st 4MB would be DMA. The apple IIGS CANNOT do DMA above 4MB of ram no matter what ram card you have. Having more than 4MB in your Octoram should work fine, just realize that properly built hardware will not even try to do DMA to any memory above 4MB. Seymour Joseph
whitewolf@gnh-starport.cts.com (Tae Song) (04/20/91)
------------------------------ Stuff Deleted -------------------------------- |I also have an OctoRAM card. I have 2-1MB parts in it and have no problem |running with my RamFAST with DMA enabled and my TWGS. My understanding is |that no matter how many slots for ram your card has, the Apple IIGS will only |do DMA to the first 4 rows (SIMMs) for a maximum of 4 meg. If you use 256k |parts in the Octoram, that means that only the 1st Meg would be DMA (not good) |If you use 1MB parts, only the 1st 4MB would be DMA. The apple IIGS CANNOT |do DMA above 4MB of ram no matter what ram card you have. Having more than |4MB in your Octoram should work fine, just realize that properly built |hardware will not even try to do DMA to any memory above 4MB. Oh no. DMA is limited to the first 4MB, not 4 first row. It doesn't matter if you use 256K or 1, 2 or 4MB SIMMs. It's just 4MB. INET: whitewolf@gnh-starport.cts.com UUCP: crash!gnh-starport!whitewolf ARPA: crash!gnh-starport!whitewolf@nosc.mil
daveh@ccwf.cc.utexas.edu (Dave Huang) (04/20/91)
In article <m0jU6xy-00003oC@jartel.info.com> whitewolf@gnh-starport.cts.com (Tae Song) writes: >|running with my RamFAST with DMA enabled and my TWGS. My understanding is >|that no matter how many slots for ram your card has, the Apple IIGS will only >|do DMA to the first 4 rows (SIMMs) for a maximum of 4 meg. If you use 256k >|parts in the Octoram, that means that only the 1st Meg would be DMA (not good) >|If you use 1MB parts, only the 1st 4MB would be DMA. The apple IIGS CANNOT >|do DMA above 4MB of ram no matter what ram card you have. Having more than >|4MB in your Octoram should work fine, just realize that properly built >|hardware will not even try to do DMA to any memory above 4MB. I thought that if the card does its own address mapping, it's possible to DMA over 4 rows. Isn't the GSRAM+ DMA compat up to 6MB? >Oh no. DMA is limited to the first 4MB, not 4 first row. It doesn't matter if >you use 256K or 1, 2 or 4MB SIMMs. It's just 4MB. Nah, DMA is normally limited to the first 4 rows in a GS... No RAMcard currently available for the GS takes 2 or 4MB SIMMs. >INET: whitewolf@gnh-starport.cts.com >UUCP: crash!gnh-starport!whitewolf >ARPA: crash!gnh-starport!whitewolf@nosc.mil -- David Huang | Internet: daveh@ccwf.cc.utexas.edu | "How much is that hamster UUCP: ..!ut-emx!ccwf.cc.utexas.edu!daveh | in the window?" America Online: DrWho29 |
mvk@aix01.aix.rpi.edu (Michael V. Kent) (04/21/91)
So, back to my original question. If I plug 8 256K SIMMs into my OctoRAM with
my Apple High Speed (DMA) SCSI card, what happens? Will I get 1 Meg of DMA and
1 Meg of non-DMA; or just 1 Meg of DMA; or an unusable system, or damaged hard-
ware?
I've been told that with an Apple SCSI card, only the first 4 SIMMs will
function in any way. With a RAMFast SCSI, I've been told, the first 4 SIMMs
will be DMA, and the second 4 SIMMs will function normally. Is this true?
What's the scoop?
--
Michael Kent mvk@itsgw.rpi.edu
McDonnell Douglas Rensselaer Polytechnic Institute
St. Louis, Missouri Troy, New York
Apple II Forever!gwyn@smoke.brl.mil (Doug Gwyn) (04/21/91)
In article <m0jU6xy-00003oC@jartel.info.com> whitewolf@gnh-starport.cts.com (Tae Song) writes: >Oh no. DMA is limited to the first 4MB, not 4 first row. It doesn't matter if >you use 256K or 1, 2 or 4MB SIMMs. It's just 4MB. Quite to the contrary. I found out the hard way with 8 256KB chips in my OctoRAM.
toddpw@nntp-server.caltech.edu (Todd P. Whitesel) (04/21/91)
mvk@aix01.aix.rpi.edu (Michael V. Kent) writes: >So, back to my original question. If I plug 8 256K SIMMs into my OctoRAM with >my Apple High Speed (DMA) SCSI card, what happens? Will I get 1 Meg of DMA and >1 Meg of non-DMA; or just 1 Meg of DMA; or an unusable system, or damaged hard- >ware? You should get an unusable system. DMA access to the upper meg will not work correctly and you probably get system crashes moments after you first use the disk. If you flip a switch on the DMA SCSI so it doesn't actually use DMA then everything will work but it will be much slower without an accelerator. >I've been told that with an Apple SCSI card, only the first 4 SIMMs will >function in any way. With a RAMFast SCSI, I've been told, the first 4 SIMMs >will be DMA, and the second 4 SIMMs will function normally. Is this true? Not really. It is the other way around, and with 1 meg SIMMs: Most memory cards can only support DMA for four rows of chips (i.e. 4 SIMMs). If the HD card attempts to DMA into the other rows then bad things will happen and you will get an unusable system. The DMA SCSI does not attempt to use DMA above the 4 Megabyte mark, so if you have an OctoRAM with 1 meg SIMMs it will work with 4 megs DMA, 4 megs normal. If you have 256K SIMMs in it you cannot use DMA at all with the Apple SCSI, and the RAMfast must be told to only DMA to the motherboard (both are DIP switches on the cards). The RAMfast does not to my knowledge put a limit on expansion RAM DMA so you will not be able to DMA to the OctoRAM with it. You can still DMA to the motherboard (you can ALWAYS DMA to the motherboard unless another DMA peripheral is causing a conflict -- this apparently happens if both a RAMfast and DMA SCSI are in the same system, and causes 'creeping crashes' -- trust me, I know, I had both for a week and couldn't use them together for more than five minutes without a crash). Todd Whitesel toddpw @ tybalt.caltech.edu
gwyn@smoke.brl.mil (Doug Gwyn) (04/21/91)
In article <7vpgrza@rpi.edu> mvk@aix01.aix.rpi.edu (Michael V. Kent) writes: >What's the scoop? 8 256KB SIMMs in an OctoRAM give you 2MB expansion RAM plus the 256KB on the motherboard (1.125MB if ROM03). All of it is usable for any purpose except DMA. Only the first 1MB (4 rows) of the expansion RAM is suitable for DMA. Apple's High-Speed SCSI Card will unfortunately attempt DMA to any address less than 4MB, which would include the non-DMA compatible portion of the 8x256KB OctoRAM. You could disable DMA use by the SCSI Card altogether in such a case. There simply is no way to safely use the upper 1MB of an 8x256KB OctoRAM for DMA transfers. The 8x1MB OctoRAM is a different matter. There, due to a hack in the firmware on the High-Speed SCSI Card, no DMA is attempted (by the SCSI Card) to the DMA-incompatible portion of the OctoRAM.
taob@pnet91.cts.com (Brian Tao) (04/21/91)
From whitewolf@gnh-starport.cts.com (Tae Song): > Oh no. DMA is limited to the first 4MB, not 4 first row. It doesn't matter > if you use 256K or 1, 2 or 4MB SIMMs. It's just 4MB. Just to clarify, that's 4 megabytes on the memory card PLUS whatever is on the motherboard. So a ROM 03 can actually have a tad over 5 megs for DMA. Brian T. Tao *B-) | t569taob@bluffs.scar.utoronto.ca | "Though this be U of Metro Toronto | - or - | madness, yet there Scarberia, ON | taob@pnet91.cts.com | is method in 't."