neese@adaptex.UUCP (09/10/90)
>>>If you use SCSI drives, at least some of them power-sequence themselves; >>>that's a consideration since it's the start-up power requirement that's the > >>I tried enabling the delay on power up on my SCSI Wren drives - but >>the Adaptec 1542B & ISC never finds the drives - > >Curious. I missed the first part of this thread, but it looks suspiciously >like the behavior of my 1542B/ Seagate 296N combination under Xenix 2.3.2. >On the initial power-up sequencing, the Adaptec will poll for devices >before the Seagate has finished it's recalibration. After about ten seconds >of silence, the ST296N will restart what sounds like it's power-on self >test, and the 1542B will then report it as Drive C and continue. > >Come to think of it, this is not OS specific, because it does this when I >run it under DOS as well. What the behavior you are describing is quite simple. At power on a SCSI device goes through it's self-test. Some SCSI devices will hold the SCSI bus busy during this period of time. These devices will cause a SCSI bus reset to be issued by the adapter after the SCSI bus goes free so you will see the device go through it's self test again. If a OS issues a SCSI bus reset and does not wait for the bus to clear up before going further, there is a good chance that they will not recognize the device when they get to the first issuance of a SCSI command. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ uunet!swbatl! {nominil,merch,cpe,mlite}!adaptex!neese
src@scuzzy.in-berlin.de (Heiko Blume) (09/16/90)
neese@adaptex.UUCP writes: >What the behavior you are describing is quite simple. At power on a SCSI >device goes through it's self-test. Some SCSI devices will hold the SCSI >bus busy during this period of time. These devices will cause a SCSI bus >reset to be issued by the adapter after the SCSI bus goes free so you will >see the device go through it's self test again. >If a OS issues a SCSI bus reset and does not wait for the bus to clear up >before going further, there is a good chance that they will not recognize the >device when they get to the first issuance of a SCSI command. all too true, with my three drive combo i have to reboot after i power the machine up (when the 'booting the blah' message comes) because the ST296 is too slow at startup - it doesn't show up the first time. i didn't had to do this with my old board because the ram test took longer, so installing more RAM (more than 8MB) could cure this :-) -- Heiko Blume c/o Diakite blume@scuzzy.in-berlin.de FAX (+49 30) 882 50 65 Kottbusser Damm 28 blume@scuzzy.mbx.sub.org VOICE (+49 30) 691 88 93 D-1000 Berlin 61 blume@netmbx.de TELEX 184174 intro d scuzzy Any ACU,e 19200 6919520 ogin:--ogin: nuucp ssword: nuucp
richard@pegasus.com (Richard Foulk) (09/18/90)
>all too true, with my three drive combo i have to reboot after i power the >machine up (when the 'booting the blah' message comes) because the ST296 >is too slow at startup - it doesn't show up the first time. i didn't had to >do this with my old board because the ram test took longer, so installing >more RAM (more than 8MB) could cure this :-) I had similar problems at power-up with some Wren IV's and moving to 8megs of RAM did alleviate the problem. -- Richard Foulk richard@pegasus.com