wombat@claris.com (Scott Lindsey) (03/22/90)
Since Road Runner has been announced and the press release and subsequent conversation didn't discuss too much of the technical details, I thought I'd post the blurb sheet from the preliminary documentation. High speed SCSI card for the enhanced IIe or IIgs. Major elements: * 53C80 SCSI SCSI interface chip * Custom gate array chip * 8 KB of RAM (8 banks of 1Kbyte each) * 32 KB of ROM (32 banks) * Page latches for RAM and ROM * SCSI Address and DMA Enable/Disable switches * 1/4 second watchdog timer * Buffers, I/O decoders, and timing circuitry Features: * Programmed I/O, Pseudo DMA, and real DMA supported * DMA transfers up to 64K in length * DMA stops on interrupts, address rollover from $FFFF to $0000, and watchdog timeout * DMA speed is up to 1MB/sec * DMA speed can be limited to 500KB/sec, to work with 65C02 processors * Will suspend DMA activity if higher priority DMA device needs the bus (Apple II DMA priority chain) ** IMPORTANT: In order for DMA to work right, the system must be running at 1MHz. [This was from preliminary docs, so details may have changed] Scott Lindsey | I dig iguana in their outer space duds Claris Corp. | saying, "Aren't you glad we only eat bugs?" ames!claris!wombat| DISCLAIMER: These are not the opinions of Claris, Apple, wombat@claris.com | StyleWare, the author, or anyone else living or Dead.
unknown@ucscb.UCSC.EDU (The Unknown User) (03/22/90)
In article <WOMBAT.90Mar21131421@claris.com> wombat@claris.com (Scott Lindsey) writes: >** IMPORTANT: In order for DMA to work right, the system must be running at >1MHz. WAIT one darn second... So you mean I can't run my GS at full speed with this thing and DMA running??? So I either get 1 mHz [thus cruddy performance of ANYTHING GS specific] and 1 meg/second max OR 2.8 mHz and .5 second/max [and cruddy performance of the SCSI card comparatively]??? Boy that seems like one --HUGE-- flaw to me... And I was about to go out and get one of these new SCSI cards (if I could find one) and a cartridge drive for my GS.. Maybe I should find more info about this thing first! -- _ __ __ __ _ /-------------------------------\ /_\ |__| | __| |_| |_ \ / |_| | unknown@ucscb.ucsc.edu | / \ | |__ |__ | |__ \/ | \ | unknown%darkside.com@ames.arpa | \-------------------------------/
toddpw@tybalt.caltech.edu (Todd P. Whitesel) (03/22/90)
To Unknown user: don't worry about it! the SCSI driver will slow down just before it starts the DMA and then go back to fast when it's finished. Todd Whitesel toddpw @ tybalt.caltech.edu
gwyn@smoke.BRL.MIL (Doug Gwyn) (03/23/90)
In article <7114@ucdavis.ucdavis.edu> unknown@ucscb.UCSC.EDU (The Unknown User) writes: >In article <WOMBAT.90Mar21131421@claris.com> wombat@claris.com (Scott Lindsey) writes: >>** IMPORTANT: In order for DMA to work right, the system must be running at >>1MHz. > Boy that seems like one --HUGE-- flaw to me... Me too. I would hope that the DMA SCSI card, or at the very least the GS/OS driver for it, it smart enough to shift the Apple IIGS into slow mode temporarily (if indeed this is a restriction) then restore it to its original speed when the I/O transfer is done.
wombat@claris.com (Scott Lindsey) (03/23/90)
In article <7114@ucdavis.ucdavis.edu> unknown@ucscb.UCSC.EDU (The Unknown User) writes: > In article <WOMBAT.90Mar21131421@claris.com> wombat@claris.com (Scott Lindsey) writes: > >** IMPORTANT: In order for DMA to work right, the system must be running at > >1MHz. > WAIT one darn second... > So you mean I can't run my GS at full speed with this thing and DMA > running??? So I either get 1 mHz [thus cruddy performance of ANYTHING GS > specific] and 1 meg/second max OR 2.8 mHz and .5 second/max [and cruddy > performance of the SCSI card comparatively]??? NonononoNO! As I noted, that was quoted from technical documentation -- not intended for casual perusal: the machine does have to be running at 1MHz but it is quite capable of changing speeds on its own -- this is done for all I/O currently anyway. That comment was intended for developers who might actually have to deal with the situation and not for end users. Scott Lindsey | I dig iguana in their outer space duds Claris Corp. | saying, "Aren't you glad we only eat bugs?" ames!claris!wombat| DISCLAIMER: These are not the opinions of Claris, Apple, wombat@claris.com | StyleWare, the author, or anyone else living or Dead.
shatara@memit.enet.dec.com (Chris Shatara) (03/23/90)
In article <WOMBAT.90Mar21131421@claris.com>, wombat@claris.com (Scott Lindsey) writes... > > >** IMPORTANT: In order for DMA to work right, the system must be running at >1MHz. > This seems crazy! I would think that IIgs owners would leave the machine at the FAST setting [2.7+/- MHZ] to take advantage of all the speed they can get. Now this is telling us we need to drop the machine to the NORMAL setting *&^%?? Please say it aint so :-( ============================================================================= | Chris Shatara | Internet: shatara@memit.enet.dec.com | | Opinions expressed are | DEC Easynet: memit::shatara | | mine and mine only! | UUCP: ...!decwrl!memit!shatara | =============================================================================
cwilson@NISC.SRI.COM (Chan Wilson) (03/23/90)
In article <WOMBAT.90Mar21131421@claris.com> wombat@claris.com (Scott Lindsey) writes: > >Since Road Runner has been announced and the press release and subsequent >conversation didn't discuss too much of the technical details, I thought >I'd post the blurb sheet from the preliminary documentation. [neato techie details nuked] Arriving at your local dealer in approximately two weeks! At least, that's what the 4 dealers I talked to all said.. :( >Scott Lindsey | I dig iguana in their outer space duds --Chan ................ Chan Wilson -- cwilson@nisc.sri.com <!> I don't speak for SRI. Janitor/Architect of comp.binaries.apple2 archive on wuarchive.wustl.edu "And now, the penguin on top of the television set will explode." ................
gwyn@smoke.BRL.MIL (Doug Gwyn) (03/24/90)
In article <14560@fs2.NISC.SRI.COM> cwilson@NISC.SRI.COM (Chan Wilson) writes: >Arriving at your local dealer in approximately two weeks! One Apple dealer I talked to had no plans to order DMA SCSI cards until the several old SCSI cards he already had in stock were sold. Of course that should take forever if the customers are aware, and is unethical if they are unaware. Doesn't Apple have some policy for trading obsolete dealer inventory? Apparently they failed to tip off the dealers that they shouldn't stock up on the old cards..