eichelbe@nadc.ARPA (11/04/85)
In the near future we will be installing 3 DEC RA81 disk drives and
a UDA50 controller onto our VAX 11/780, which is running 4.1 (NOTE: that's 4.1)
BSD UNIX. We do not have anything like the newfs utility on 4.2 BSD. We are
stuck using the 4.1 BSD utility mkfs(8). The call to this utility is of the
form: /etc/mkfs special size [m n]
(at least how we use it). The man page for mkfs(8) says that the 'special'
parameter is the file partition (e.g., /dev/rhp2g) and the 'size' parameter is
the size of the file system in kilobytes. No problem so far. Now, although
the manual page seems to specify the 'm' and 'n' parameters as optional, we
have always supplied them as the manual page says 'm' should always be 3 and 'n'
should be as given in the following table:
RM03 80
RM05 304
RM80 217
RP06 209
RP07 800
SI/CDC 9766 304
RK07 33
EMULEX/AMPEX 300M 304
EMULEX/FUJITSU 160M 160
The manual page calls the 'm n' pair the interleave factor. What does this
mean? Since there was an 'n' for the SI/CDC 9766 drives we have, there was
no problem. But there is no entry for an RA81. My questions are:
(1) Is it OK to leave off 'm' and 'n', and will the mkfs(8) utility do the
'right thing' for me? For an SI/CDC 9766? FOR AN RA81???!!!
(2) If I want to specify 'm' and 'n' for the RA81, what should the values be?
Again, let me stress that I am under 4.1 BSD UNIX, and I have no newfs
utility.
(3) Although this is the least important question, how do you figure out
'm' and 'n', given a brand X drive with a brand Y controller for it?
(Actually, this may be the most important question in the long run.)
Thanks.
Jon Eichelberger
eichelbe@NADC.ARPACrispin@SUMEX-AIM.ARPA (Mark Crispin) (11/04/85)
The "size" paramater you referred to doesn't look like anything in kilobytes or megabytes. But for comparitive purposes, here's what disk parameters are for various kinds of disks, as seen by TOPS-20: Disk RECSIZ TRKSIZ CYLSIZ DSKSIZ RP04 128 20 19 400 RP06 128 20 19 800 RP07 128 43 32 629 RM03 128 30 5 820 RA80 512 7 28 273 RA81 512 161 1 128 RA60 512 38 1 2382 RECSIZ := number of 36-bit words/record TRKSIZ := number of records in a track CYLSIZ := number of tracks/cylinder (number of surfaces) DSKSIZ := number of cylinders -------
chris@umcp-cs.UUCP (Chris Torek) (11/05/85)
> ... for comparitive purposes, here's what disk parameters are > for various kinds of disks, as seen by TOPS-20: > > Disk RECSIZ TRKSIZ CYLSIZ DSKSIZ > [...] > RA81 512 161 1 128 > [...] > RECSIZ := number of 36-bit words/record > TRKSIZ := number of records in a track > CYLSIZ := number of tracks/cylinder (number of surfaces) > DSKSIZ := number of cylinders That is interesting---and wrong. There are 14 tracks per cylinder. In normal terms (I have no idea how you stuff 512 36 bit words into a 512 byte sector) RA81s have 512 bytes per sector, 51 sectors per track, 14 tracks per cylinder, and 1248 cylinders, for a total of 891072 blocks or 456,228,864 bytes (~450Mb). -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251) UUCP: seismo!umcp-cs!chris CSNet: chris@umcp-cs ARPA: chris@mimsy.umd.edu