scotte@applix.com (Scott Evernden) (01/04/91)
I couldn't get an answer from Adaptec tech. or any local distributors, and no one's calling me back, so I ask you- what's the max bus speed rating for the 1542B? -scott
neese@adaptx1.UUCP (01/08/91)
>/* ---------- "Adaptec AHA1542B max bus speed" ---------- */ >I couldn't get an answer from Adaptec tech. or any local distributors, >and no one's calling me back, so I ask you- what's the max bus speed >rating for the 1542B? The 154x adapter has the ability to move data across the AT bus at up to 10MBytes/sec, but so far no one has built an AT that can allow true 10MB/sec data rates. The card may work at this setting in some systems but is actually slowed down by the IOCHRDY signal. This signal is implemented on the motherboard and very differently from manufacturer to manufacturer. There is also no jumper on the adapter for this speed setting, but can be done via software. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ neese@adaptex uunet!cs.utexas.edu!utacfd! {nominil,merch,cpe}!adaptex!neese uunet!mlite!adaptex!neese
ssingh@watserv1.waterloo.edu (The Sanj-Machine aka Ice) (01/13/91)
In article <284500010@adaptx1> neese@adaptx1.UUCP writes: > >There is also no jumper on the adapter for this speed setting, but can be >done via software. > > Roy Neese From: aha-1540B/1542B user's manual rev 0.3 Dec. 1989 3.3.1.7 DMA Transfer Speed Default Pin-pairs 12 and 13 of jumper block J5 set the default DMA transfer speed. [stuff skipped] This speed may also be tuned to allow for the fastest possible transfer (minimum bus on time) for any particular system by using the Host Adapter command Set Transfer Speed. The Host Adapter command overrides the jumper settings. Pin Pair DMA Speed 12 13 ============================================================ 0 0 5.0 MB/s x 0 5.7 0 x 6.7 x x 8.0 5.0 MB/s is the default. I was able to get the adapter and Seagate ST 296N drive working at the next speed up. Another version of the documentation I have for the 1540A/1542A has speeds of 5.0, 6.7, 8.0, 10, and then 5.7. This is section 5.1.1.10. These inconsistencies are irritating. But Adaptec is widely supported so I guess they must be doing something right. Ice. -- "No one had the guts... until now!" $anjay $ingh Fire & "Ice" ssingh@watserv1.[u]waterloo.{edu|cdn}/[ca] ROBOTRON Hi-Score: 20 Million Points | A new level of (in)human throughput... "The human race is inefficient and therefore must be destroyed."-Eugene Jarvis