Adaptec 1540A, two HDs, one tape

James O'Connor jim at bahamut.fsc.com
Thu Nov 23 01:10:25 AEST 1989


In article <1989Nov17.044859.7911 at NCoast.ORG>, mikes at NCoast.ORG (Mike Squires) writes:
> In article <935 at puck.UUCP> asp at puck.UUCP (Andy Puchrik) writes:
> >	Does the Adaptec SCSI controller support both disks and tapes?
> >How many devices can it support?  Ideally, I'd like to have two disks
> >and one tape driver.  What kind of performance do you get with an Archive
> >Viper with a SCSI interface?
> 
> I am using an Adaptec 1540A controller in a Tandy 4000LX with a CDC 340MB
> primary and a Micropolis 660MB secondary HD, plus a Cipher 150II SCSI tape
> drive.  Disk throughput running "tar" in multiuser mode using the "monitor"

We're also using SCSI here under SCO Xenix 2.3GT.  Here's what we look like:

Host Adapter 1:	Adaptec 1540 (as sold by Tandy)
		CDC Wren V 190MB Half-Height drive
		Quantum Q280 80MB Half-Height drive (as sold by Tandy)

Host Adapter 2:	Adaptec 1540A (as sold by Tandy)
		Syquest SQ555 44MB removeable hard drive
		Archive Viper 150MB Tape drive

We went to the split host adapter configuration because of an apparent
conflict on the SCSI bus between the CDC and Syquest drive.  They both work
fine, and perform great, on separate busses, but put them on the same bus, and
lock ups start occuring at a rapid pace.  This may be due to my particular
drives, and is not a blanket statement about all CDC or Syquest drives.
The tape performance is great.  It streams when using tar (or ctar) about
70% of the time, and almost always streams when it's just skipping over files
that it's not writing to the disk (i.e. doing "tar xvf /dev/rct0 file" where
"file" is near the end of the tape will be fairly painless cause the tape
drive will stream 97% of the time until it finds "file").

We haven't had any trouble with the multi-host-adapter set up, and we have even
used a normal WD controller in the same system for a while without trouble.
The Adaptec 1540A has an external connector on it, so I'm looking forward to
being able to add another drive or two when I need it.
------------- 
James B. O'Connor			Work:	jim at tiamat.fsc.com
Filtration Sciences --			Play:   jim at bahamut.fsc.com
A division of Ahlstrom			UUCP:	uunet!tiamat!jim



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