[comp.sys.hp] What are good disktab entries for the new HP670H disk drive?

wehr@fmsrl7.UUCP (Bruce Wehr ) (04/05/91)

Howdy,

We've got one of HP's new Series 6000 Model 670H disk drives. This is a
670Mb drive with the following geometry:

     256 bytes/sector
     113 sectors/track
      16 tracks/cylinder
    1449 cylinders

Since this is a new disk, there is no entry in /etc/disktab. No
problem, I'll roll my own. But the utilities that use disktab want to
talk about 1Kb sectors, not 256 byte sectors. So I sacrificed one 256
byte sector per track, claiming I've got 28 1Kb sectors/track. It
works, but it also works out to be nearly 6Mb being tossed out the
window (which I'd rather not do if I don't have to).

Here's an excerpt from /etc/disktab that talks about "fudging" disktab
numbers to solve a similar problem (ns#X represents the number of
sectors/track):

    #       ns#X  must be in multiples of 1k.  We must sometimes     #
    #       then "fudge" the numbers.  Example: A gray microfloppy   #
    #       formatted with format option 2 has this geometry:        #
    #          - 512 bytes/sector                                    #
    #          -   9 sectors/track                                   #
    #          -  77 tracks/surface                                  #
    #          -   2 surfaces                                        #
    #                                                                #
    #       We have to fool option 2, instead of 9 sectors of 512    #
    #       bytes with 2 heads, we specified 9 sectors of 1K with    #
    #       1 head (ns# REQUIRES 1K).                                #

This example look pretty clean. I'm sure I could come up with some
numbers that work out to represent the whole disk, but it wouldn't be
as clean as the example. It would probably work - but, I'm afraid I'd
kill disk performance.

Finally, the question: do I need to sacrifice 1% of my disk in the name
of performance (which I'm more than willing to do)? Or is there
something else I can do to use the entire disk without sacrificing
performance?

Any and all advice is appreciated (except RTFMs - I've done that).

As a second, minor question: /etc/disktab refers several times to a
'cs80describe' utility - I have no such beast. What's up? I think I saw
this question go by a while ago - and I didn't pay attention to the
responses.  Deserving flames tolerated - as long as they're accompanied
by useful information.

Thanks.
-- 
               Bruce Wehr (wehr%dptc.decnet@srlvx0.srl.ford.com)
                (..!uunet!srlvx0.srl.ford.com!wehr%dptc.decnet)
              Ford Motor Company - Engineering Technology Services
     P.O. Box 2053, Room 1153, Dearborn, Michigan 48121-2053 (313)337-5304

franks@hpuamsa.neth.hp.com (Frank Slootweg CRC) (04/08/91)

  You did not specify the Series (300/400/600/800) or the Release. Because
the "cs80describe" which you mentioned (and which I do not know anything
about) is only mentioned in the Series 300/400 disktab, I will assume
Series 300/400 and 7.0 (but the story is also valid for 7.0 on the other
mentioned Series).

> Since this is a new disk, there is no entry in /etc/disktab.

  It is somewhat new but the entry should be in /etc/disktab for the
above mentioned Series and Release.
  Make sure that you have the 7.0 disktab from /etc/newconfig and use
the model *number* of your disk, not the model *name* (Believe it or
not, your "Series 6000 Model 670H" is the name, not the number. It's all
marketing jive and yes your car has a similar name versus number-for-
ordering-purposes distiction.).
  The model number is probably (Heh, I'm just a software type!) on the
serial number (Heh, great YAN!) identification plate/sticker. It
probably is (HP) 2203A and if so search on 2203 in your
/etc/newconfig/disktab.

  Hope this helps.

Frank Slootweg "My car is a 897056-325A-G/002AD but I like it anyway",
Dutch Customer Response Center.

thomas@hpugrca.HP.COM (Thomas Buenermann) (04/09/91)

/etc/[newconfig/]disktab from 7.0:

# @(#) $Revision: 64.6 $
...
# HP2203A has 671 MBytes
#         256 Bytes/sector
#         113 sectors/track;  16 heads;  1449 cylinders;
#       Total: 654948 1K sectors
hp2203A|hp22030:\
        :64 MBytes swap:ns#113:nt#4:nc#1304:\
        :s0#589408:b0#8192:f0#1024:\
        :se#256:rm#3600:
hp2203A_96MB|hp22030_96MB:\
        :96 MBytes swap:ns#113:nt#4:nc#1231:\
        :s0#556412:b0#8192:f0#1024:\
        :se#256:rm#3600:
hp2203A_42MB|hp22030_42MB:\
        :42 MBytes swap:ns#113:nt#4:nc#1353:\
        :s0#611556:b0#8192:f0#1024:\
        :se#256:rm#3600:
hp2203A_noswap|hp22030_noswap:\
        :noswap:ns#113:nt#4:nc#1449:\
        :s0#654948:b0#8192:f0#1024:\
        :se#256:rm#3600:

dlj@hpfcdc.HP.COM (David Jobusch) (04/09/91)

/ hpfcdc:comp.sys.hp / wehr@fmsrl7.UUCP (Bruce Wehr ) / 10:11 am  Apr  4, 1991 /
>Howdy,
>
>We've got one of HP's new Series 6000 Model 670H disk drives. This is a
>670Mb drive with the following geometry:
>
>     256 bytes/sector
>     113 sectors/track
>      16 tracks/cylinder
>    1449 cylinders
>

I found an entry for the "HP2203A" (which I think is your drive)
on 7.05 systems - don't know if it made it in for 7.0. 
Here is the disktab entry for the HP2203A from 8.0:

# HP2203A has 671 MBytes
#         256 Bytes/sector
#         113 sectors/track;  16 heads;  1449 cylinders;
#       Total: 654948 1K sectors
hp2203A|hp670H|hp2203|hp22030:\
	:64 MBytes reserved for swap & boot:ns#113:nt#4:nc#1304:\
	:s0#589408:b0#8192:f0#1024:\
	:se#256:rm#4002:
hp2203A_96MB|hp670H_96MB|hp22030_96MB:\
        :96 MBytes reserved for swap & boot:ns#113:nt#4:nc#1231:\
        :s0#556412:b0#8192:f0#1024:\
        :se#256:rm#4002:
hp2203A_42MB|hp670H_42MB|hp22030_42MB:\
        :42 MBytes reserved for swap & boot:ns#113:nt#4:nc#1353:\
        :s0#611556:b0#8192:f0#1024:\
        :se#256:rm#4002:
hp2203A_noreserve|hp2203A_noswap|hp670H_noreserve|hp670H_noswap:\
        :no swap or boot:ns#113:nt#4:nc#1449:\
        :s0#654948:b0#8192:f0#1024:\
        :se#256:rm#4002:
hp22030_noreserve|hp22030_noswap:\
        :no swap or boot:ns#113:nt#4:nc#1449:\
        :s0#654948:b0#8192:f0#1024:\
        :se#256:rm#4002:
	

Hope this helps...

         ___        Dave Jobusch
        /  /        HP Fort Collins, CO
HEWLETT/hp/PACKARD  OSSD/UDL 68K Kernel Project
      /__/          dlj@hpfcls.hp.com