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From: alan@wam.umd.edu (Alan Joseph Schunemann)
Newsgroups: comp.sys.next
Subject: Re: NeXT HDs, who makes them?
Keywords: NeXT HDs, transfer rates, sizes
Message-ID: <1991Feb3.141109.26388@wam.umd.edu>
Date: 3 Feb 91 14:11:09 GMT
References: <63452@brunix.UUCP> <1991Feb3.025412.9529@agate.berkeley.edu>
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In article <1991Feb3.025412.9529@agate.berkeley.edu> 39clocks@violet.berkeley.edu (Peter Marinac) writes:
>
>Looking at a NeXT product brochure I noticed that the "Mass Storage Options"
>for the cube are not described in a consistent manner.  I know that the 660Mb
>and late 330Mb drives are made by MAXTOR, and ads for the NeXTStation reveal
>that the 105 is a low profile Quantum, but what about the others?  And what's
>the difference between: raw burst transfer rate, maximum transfer rate
>(syncronous), and sustained transfer rate.  I mean I can guess what they terms
>mean, but how do they effect "real world" operations?
>
>Here is how NeXT describes the hard disk it sells for the cube:
>
>200 MB Hard Disk Drive (optional)
>    3.5", 1/2-height, 200MB formatted capacity, 15msec avg seek, 4 MBytes/sec
>    transfer rate(syncronous).  (Made by:?)
	I believe it's made by Conner.

>400 MB Hard Disk Drive (optional)
>    3.5", 1/2-height, 406MB formatted capacity, 13msec avg seek, 4 Mbytes/sec
>    transfer rate(synchronous). (Made by:?)
	  Hewlett Packard.

>1.4 GB Hard Disk Drive
>    5.25" full height, 1.4 GB formatted capacity, 13ms avg seek, 4 Mbytes/sec
>    maximum transfer rate.  (Made by: ?)
	This one is in the disktab. It's a Maxtor  (2.0)

>Interestingly enough, the same brochure states that the SCSI-2 connector has
>a transfer rate of 4.8MB/sec (burst rate), but does not specify a sustained
>rate, nor a rate for the internal port. 
>
>last question:  Is synchronous communication uniqe to SCSI-2 drives?
>            Thanks alot,   Peter Marinac, 39clocks@violet.berkeley.edu

I don't believe synchronous communication is "unique" to SCSI-2 drives. The 
Quantum 105 LPS internal drive runs synchronous. (that's what LPS stands for).
Most of the "big" workstation manufacturers package synchronous HDs with thier
systems because they're faster. I've been trying to figure this whole HD mess
out for a while and the above comments are just my current understanding not
the gospel. If anyone knows the real spiel please correct me!

Thanks,
Alan

--
_______________________________________________________________
Alan Schunemann       Well, what shall we throw away this year?
alan@wam.umd.edu      -Andrew Carnegie