From: guyd@austin.ibm.com (Guy Dawson)
Subject: Re: SCSI or IDE: The Bottom Line
Originator: guyd@pal500.austin.ibm.com
Organization: IBM Austin
Lines: 73


In article <1993Apr22.192408.2272@msc.cornell.edu>, Randy Ellingson writes:
> Which would YOU choose, and why?

I have both!

I have IDE only on my DROS box and IDE and SCSI on my Unix box.

IDE on the DROS box 'cos it only has a hard disk, SCSI on my Unix box 'cos it
has a SCSI hard disk, CD-ROM and tape.

I bought SCSI as it makes adding many devices easier. For the price of one
irq and dma I have three different types of device connected up.

Faster drives are also available for SCSI - I have a DEC DSP3085s that realy
does have a 9ms average seek time. I.E it finds data 25% faster than my 12ms
Toshiba drive.

> 
> Like lots of people, I'd really like to increase my data transfer rate from
> the hard drive.  Right now I have a 15ms 210Mb IDE drive (Seagate 1239A), and
> a standard IDE controller card on my ISA 486-50.

I don't think that SCSI will increase your data transfer much on an ISA bus :-(

> 
> I'm currently thinking about adding another HD, in the 300Mb to 500Mb range.
> And I'm thinking hard about buying a SCSI drive (SCSI for the future benefit).
> I believe I'm getting something like 890Kb/sec transfer right now (according
> to NU).

890KB/s is pretty good...

> 
> How would this number compare if I bought the state-of-the-art SCSI card for
> my ISA PC, and the state-of-the-art SCSI hard drive (the best system I could
> hope for)?

Many state of the art SCSI disks use the *SAME* mechanicals as many state of the
art IDE drives. Only the interface electronis differ - look at the 520MB Fijitsu
drive for an example!

> 
> Obviously money factors into this choice as well as any other, but what would
> YOU want to use on your ISA system? And how much would it cost?

I use an Adaptec 1542B on my Unix box and no-name IDE cards on both.

> 
> Along those lines, what kind of transfer rate could I see with my IDE HD's if I
> were to buy the top-of-the-line IDE caching controller for my 200Mb, 15ms HD?
> And how much would it cost?

Caching controller! Why? What does it give you that smartdrive ( for DOS ) does 
not? About 30KB extra lower memory! That's about it.

A properly configured main memory cache will produce better results than a caching
controller! My Unix reads reads data from its main memory cache at 8.5MB/s! That's
faster than the standards ISA bus can ever sustain!


> 
> Thanks for any comments.
> 
> Randy
>   

Guy
-- 
-- -----------------------------------------------------------------------------
Guy Dawson - Hoskyns Group Plc.
        guyd@hoskyns.co.uk  Tel Hoskyns UK     -  71 251 2128
        guyd@austin.ibm.com Tel IBM Austin USA - 512 838 3377
