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Article #140102090a direct SCSI
From: Patrick John Horgan
Date: Sat, 03 Mar 1990 08:30
Date: Sat, 03 Mar 1990 08:30
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1245 bytes
A friend of mine who's hacking a tape backup disassembled the driver for the 2090a and found out why the dern thing won't do direct SCSI writes. It seems that the high order bit of one of the DMA registers specifies read or write, and the code never pulls up the put for write. He also found a workaround. He set bit 24 (the 25th bit counting 0), of the data buffer address. Only 24 bits are used (0-23), but the higher bits aren't checked or cleared. This bit position luckily gets slid in to the high bit of the DMA register causing write to work:) He told me the day before yesterday that he's been able to write to a SCSI tape drive with the 2090a, and hopes to have a driver written soon. Patrick Horgan phorgan@cup.portal.com
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Path: arc1-ca.pugleaf.net!utzoo!mnetor!tmsoft!torsqnt!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!wuarchive!texbell!texsun!newstop!sun!imagen!atari!portal!portal!cup.portal.com!phorgan From: phorgan@cup.portal.com (Patrick John Horgan) Newsgroups: comp.sys.amiga.tech Subject: 2090a direct SCSI Message-ID: <27494@cup.portal.com> Date: 3 Mar 90 08:30:34 GMT References: <10910@june.cs.washington.edu> Organization: The Portal System (TM) Lines: 13