[comp.sys.att] wanted info on 7300 disk drives

rs@mhuxu.UUCP (Bob Sanderman) (05/09/87)

I need to increase the amount of disk space on my 7300.  I currently have
a 20MB hard disk.  I know about the $800 40 MB NEC drive from Amperfax
but am looking for something bigger (internal or external).  What types
of things have other people done?  When will the 7300 support more than
one drive?

Thanks
Bob Sanderman
ihnp4!mhuxu!rs

avr@hou2d.UUCP (Adam V. Reed) (05/11/87)

In article <6485@mhuxu.UUCP>, rs@mhuxu.UUCP (Bob Sanderman) writes:
> I need to increase the amount of disk space on my 7300.  I currently have
> a 20MB hard disk.  I know about the $800 40 MB NEC drive from Amperfax
> but am looking for something bigger (internal or external).  What types
> of things have other people done?  When will the 7300 support more than
> one drive?
> 
> Thanks
> Bob Sanderman
> ihnp4!mhuxu!rs

Your 7300 diagnostic disc tells you all the acceptable types of
HD drives in the HD formatting menu. This includes a 67MB drive.
I mounted one externally with its own power supply; to do this
you have to make your own cables - same as standard but longer -
to go from the built-in controller to the external drive.
					Adam Reed

davidsen@steinmetz.steinmetz.UUCP (William E. Davidsen Jr) (05/12/87)

In article <6485@mhuxu.UUCP> rs@mhuxu.UUCP (Bob Sanderman) writes:
>I need to increase the amount of disk space on my 7300.  I currently have

As far as I can tell you can use any disk with an ST506 interface. I have
used the 32MB half-height Tulin TU-340A (now discontinued), and tried
Seagates (80MB) and Priams (72MB). You can describe the format in terms
of tracks, etc, when you do the low level format. If you have a real power
hog you may have to use an external power supply.

-- 
bill davidsen			sixhub \	ARPA: wedu@ge-crd.arpa
      ihnp4!seismo!rochester!steinmetz ->  crdos1!davidsen
				chinet /
"Stupidity, like virtue, is its own reward"

dpw@unisec.usi.com (Darryl P. Wagoner) (05/13/87)

In article <1390@hou2d.UUCP> avr@hou2d.UUCP (Adam V. Reed) writes:
>In article <6485@mhuxu.UUCP>, rs@mhuxu.UUCP (Bob Sanderman) writes:
>> I need to increase the amount of disk space on my 7300.  I currently have
>> a 20MB hard disk.  I know about the $800 40 MB NEC drive from Amperfax
>> but am looking for something bigger (internal or external).  What types
>> of things have other people done?  When will the 7300 support more than
>> one drive?
>
>Your 7300 diagnostic disc tells you all the acceptable types of
>HD drives in the HD formatting menu. This includes a 67MB drive.
>I mounted one externally with its own power supply; to do this
>you have to make your own cables - same as standard but longer -
>to go from the built-in controller to the external drive.


The Unix PC will support a lot of different disk drives.  To get a partial
list look in /usr/lib/iv.

I just upgraded to a Seagate ST251 for example which is a 40 meg/ 40 ms
drive for about $550.00.  Wow, do I have disk space now!

I also know that the Seagate ST4096 will work VERY WELL on the Unix PC.
The rule of thumb is that almost any drive that is ST506 interface will
work.  Just be sure of the power requirements of the drive,  you may
need an external power supply.

-- 
Darryl Wagoner			
UniSecure Systems, Inc.; 		dpw@unisec.usi.com
Newport,  RI; (401)-849-0857 
UUCP:  {gatech|mirror|cbosgd|uiucdcs|ihnp4}!rayssd!unisec!dpw

daveb@rtech.UUCP (05/14/87)

In article <5970@steinmetz.steinmetz.UUCP> davidsen@kbsvax.steinmetz.UUCP (William E. Davidsen Jr) writes:
>In article <6485@mhuxu.UUCP> rs@mhuxu.UUCP (Bob Sanderman) writes:
>>I need to increase the amount of disk space on my 7300.  I currently have
>
>As far as I can tell you can use any disk with an ST506 interface. I have
>used the 32MB half-height Tulin TU-340A (now discontinued), and tried
>Seagates (80MB) and Priams (72MB). You can describe the format in terms
>of tracks, etc, when you do the low level format. If you have a real power
>hog you may have to use an external power supply.

I am using a Priam (nee Vertex) 72M.  You can use practically any ST506
drive and roll your own format.  BUT -- you can only get at 7 heads worth
of drive because of the number of head selects brought out to the drive
connector.  This means some of the larger capacity Maxtors (f'rinstance)
can't be used to their full potential.

-dB
-- 
{amdahl, cbosgd, mtxinu, ptsfa, sun}!rtech!daveb daveb@rtech.uucp

ken@maxepr.UUCP (05/14/87)

In article <817@rtech.UUCP> daveb@rtech.UUCP (Dave Brower) writes:
>
>I am using a Priam (nee Vertex) 72M.  You can use practically any ST506
>drive and roll your own format.  BUT -- you can only get at 7 heads worth
>of drive because of the number of head selects brought out to the drive
>connector.

Although iv(1m) describes the number of heads as "This must be a
positive number not greater than 7", it will actually address 8
heads. This is the old problem of 0 thru 7 = 8. There are 3 head
select lines, which in binary notation, 111, equals the decimal
number 7, but including 000, describes 8 states.

Consider this;

The current hard disk driver on the 7300/3B1 is limited to 8 heads,
1024 cylinders.

Number of tracks = heads x cylinders. Each track has 17 sectors,
each sector is 512 bytes. The 7300 reserves the last sector of each
track as an alternate bad block, leaving 16 available sectors. The
maximum hard disk capacity on a 7300 is then:

8 x 1024 x 16 x 512 = 67,108,864 bytes.

Which is exactly the maximum capacity advertized for a 3B1, and also
what I achieved by adding an ST4096, which has 9 heads, 1024
cylinders.
-- 

Ken Brassler {ihnp4|qantel|pyramid|lll-crg}!ptsfa!maxepr!ken
			   ....ethos!gladys!ptsfa!maxepr!ken

wsm@emory.UUCP (William Mahavier) (05/17/87)

In article <6485@mhuxu.UUCP> rs@mhuxu.UUCP writes:
>I need to increase the amount of disk space on my 7300.  I currently have
>a 20MB hard disk.  I know about the $800 40 MB NEC drive from Amperfax
>but am looking for something bigger (internal or external).  What types
>of things have other people done?  When will the 7300 support more than
>one drive?

 I think the 7300 will use any disc with an ST506 interface, but you
 must be careful about the number of heads. I believe 7 is the maximum
 number it can handle.

W. S. Mahavier              | {akgua,sb1,gatech}!emory!wsm  USENET
Emory University            | wsm@emory ARPA,BITNET,CSNET
Dept of Math and CS         |
Atlanta, Ga 30322           | Office phone: 404-727-7585