herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) (07/18/90)
Here is a summary of the information I received regarding AT bus scsi cards. Many thanks to the people that replied. This summary gives info on the following cards: Adaptec AHA1540B/1542B DTC 3280A Future Domain TMC830 Western Digital WD FAST-ATXT Western Digital WD 7000-FAST I have not included prices, but the above cards are priced in the approximate range of US$150 to US$550. My guess is that the WD ATXT is the cheapest, followed by DTC and Future Domain, then Adaptec and finally the WD 7000 (the most expensive). All things considered, Adaptec seems to be the way to go. However, all of the cards mentioned are most likely very good except for the WD FAST-ATXT. Cheers, Andrew --- Adaptec AHA1540B/1542B ---------------------- * Maximum SCSI->AT transfer rate: 10M bytes/s (motherboard-dependent). (Bus master DMA, => card drives bus directly, not via the PC's DMA controller.) * Synchronous transactions (i.e. scsi-2) supported. * Onboard cpu handles SCSI protocol and allows the card to be used like a standard MFM controller (presumably at the BIOS level) by mapping between physical and virtual disk geometries (e.g. sectors/track, number of cylinders). * Onboard BIOS provides OS compatibility (well, DOS at least :-); SCO Unix, Interactive Unix and Esix support the controller through standard drivers. * The 1542B is the 1540B plus floppy support. DTC 3280A --------- Little is known about this card, except that it works with DOS without any special drivers. It includes floppy support. The installation guide states: "All SCSI devices that conform to the American National Standards Institute (ANSI) X3.131-1986 and Common Command Set (CCS) Rev. 4b specs are supported by the DTC31/3280A". Maximum throughput is >= 800k bytes/s (obtained using Seagate ST4376N with a 20MHz 386). "The only problem I have had is that the floppy disk drives only seem to recognise the first media density type you use after bootup i.e. if you put a high density disk in the drive, it will then not work with low density disks (they both used to work as the floppy drives are dual density). I'll probably have to go back to the dealer on that one. Apart from that I'm quite happy." Future Domain TMC830 -------------------- ISC (e.g. Interactive Unix) supports this controller. Western Digital WD FAST-ATXT ---------------------------- "The WD FAST-ATXT controller is a dog." * No intelligence, device driver required for DOS. Western Digital WD 7000-FAST ---------------------------- From comments on the net, this card is roughly equivalent in performance to the AHA1540B. There is doubt as to whether the driver for Interactive Unix 2.2 actually works.
feustel@well.sf.ca.us (David Alan Feustel) (07/21/90)
What is(are) the difference(s) between the 1542a and the 1542b?
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USMAIL: Dave Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805-2710pauls@inco.UUCP (Paul Stygar) (07/26/90)
In article <2683@bruce.cs.monash.OZ.AU> herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) writes: >Here is a summary of the information I received regarding AT bus scsi cards. >Many thanks to the people that replied. ... >I have not included prices Best price I've seen on the 1542B is at Treasure Chest (see ad in Computer Shopper for phone #) ... about $230 >Adaptec AHA1540B/1542B >---------------------- >* Maximum SCSI->AT transfer rate: 10M bytes/s (motherboard-dependent). > (Bus master DMA, => card drives bus directly, not via the PC's DMA > controller.) Where did this info come from ???? I didn't see any info in the User Manual for the 1542B to directly confirm this ... The board can be jumpered to set the DMA Transfer Speed to 5.0, 5.7, 6.7, or 8.0 MB/s (via PINS 12,13 of the J5 Jumper Block) (p. 2-9 of AHA-1540B/1542B User's Manual, Rev 1.0, April 1990). Not to mention, I don't understand this info, since the 1542B seems to run OK on an ancient (circa 1988) MICRONICS 20 Mhz motherboard which only supports 4 Mhz DMA transfer rate. -- -- | UUCP: {alembic, grebyn}!inco.UUCP!pauls (Paul Stygar) | | MDESC, 8201 Greensboro Drive, McLean, VA 22102 (703) 883-3998 | | BEGIN_DISCLAIMER;_____The_views_expressed_by_me_in_no_way_reflect_the | | views_of_McDonnell_Douglas_or_its_subsidiaries._______END_DISCLAIMER; |
poffen@sj.ate.slb.com (Russ Poffenberger) (07/27/90)
In article <8527@inco.UUCP> pauls@inco.UUCP (Paul Stygar) writes: >In article <2683@bruce.cs.monash.OZ.AU> herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) writes: >>Here is a summary of the information I received regarding AT bus scsi cards. >>Many thanks to the people that replied. > ... >>I have not included prices > > Best price I've seen on the 1542B is at Treasure Chest > (see ad in Computer Shopper for phone #) ... about $230 > >>Adaptec AHA1540B/1542B >>---------------------- >>* Maximum SCSI->AT transfer rate: 10M bytes/s (motherboard-dependent). >> (Bus master DMA, => card drives bus directly, not via the PC's DMA >> controller.) > > Where did this info come from ???? > I didn't see any info in the User Manual for the 1542B > to directly confirm this ... > > The board can be jumpered to set the DMA Transfer Speed > to 5.0, 5.7, 6.7, or 8.0 MB/s (via PINS 12,13 of the J5 Jumper Block) > (p. 2-9 of AHA-1540B/1542B User's Manual, Rev 1.0, April 1990). > > Not to mention, I don't understand this info, since the 1542B > seems to run OK on an ancient (circa 1988) MICRONICS 20 Mhz > motherboard which only supports 4 Mhz DMA transfer rate. Most likely the reason why it works is because the disk itself is the limiting factor. I have only been able to achieve an actual transfer rate of 3Mbytes/sec from a disk that has a lot of cache on it, and even then, this is really only a real benefit under very limited circumstances. (Where you happen to be reading the same disk data over and over, like some disk benchmark programs.) Russ Poffenberger DOMAIN: poffen@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!poffen 1601 Technology Drive CIS: 72401,276 San Jose, Ca. 95110 (408)437-5254
herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) (07/29/90)
In article <2683@bruce.cs.monash.OZ.AU> I wrote: >... >Adaptec AHA1540B/1542B >---------------------- >* Maximum SCSI->AT transfer rate: 10M bytes/s (motherboard-dependent). > (Bus master DMA, => card drives bus directly, not via the PC's DMA > controller.) >... In <8527@inco.UUCP> pauls@inco.UUCP (Paul Stygar) writes: > [ ref. to above information ] > Where did this info come from ???? > I didn't see any info in the User Manual for the 1542B > to directly confirm this ... > The board can be jumpered to set the DMA Transfer Speed > to 5.0, 5.7, 6.7, or 8.0 MB/s (via PINS 12,13 of the J5 Jumper Block) > (p. 2-9 of AHA-1540B/1542B User's Manual, Rev 1.0, April 1990). The 1540A/1542A manual states: 2.1.1 Bus Master DMA The AHA-1540A/1542A controls the host AT bus as a master and transfers data directly to and from main system memory. This implementation is known as Bus Master DMA. Bus Master DMA ^^^^^^^^^^^^^^ greatly reduces the host software overhead because the host CPU is no longer required to maintain the DMA channel's address pointers and word counts. ... The Adaptec AIC-560L is the DMA controller. Adaptec's implementation of Bus Master DMA can achieve a 10 MB/second burst data rate. ... ^^^^^^^^^^^^ I must admit I don't understand how this is achieved in view of the maximum jumper-selectable DMA speed of 8 Mbytes/s (perhaps the software-selected speed can go to 10Mbytes/s?), but there it is. > Not to mention, I don't understand this info, since the 1542B > seems to run OK on an ancient (circa 1988) MICRONICS 20 Mhz > motherboard which only supports 4 Mhz DMA transfer rate. This rate probably refers to the motherboard's DMA controller, not the AT bus limit. Andrew
jmerrill@jarthur.Claremont.EDU (Confusion Reigns) (08/02/90)
In article <19159@well.sf.ca.us> feustel@well.sf.ca.us (David Alan Feustel) writes: > >What is(are) the difference(s) between the 1542a and the 1542b? The 1542a is a full-length card; the 1542b uses more integrated electronics to put the same functionality on a shorter card. That's how I understand it, anyway. -- Jason Merrill jmerrill@jarthur.claremont.edu DISCLAIMER: I don't work for Adaptec.
larry@nstar.uucp (Larry Snyder) (08/02/90)
jmerrill@jarthur.Claremont.EDU (Confusion Reigns) writes: >The 1542a is a full-length card; the 1542b uses more integrated electronics >to put the same functionality on a shorter card. That's how I understand >it, anyway. But is the 1542b a faster controller? -- Larry Snyder, Northern Star Communications, Notre Dame, IN USA uucp: iuvax!ndmath!nstar!larry -or- larry@nstar Public Access Unix Site (219) 289-0282 (5 lines/PEP/HST/Hayes-V)