disk partitioning

Steve M. Burinsky smb at mimsy.umd.EDU
Wed Sep 3 09:14:05 AEST 1986


I have two questions regarding disk partitioning.  Although I think
the questions are generic, I am dealing with a RA60 and a RA81.  First,
some background for my questions.  (I hope I'm not boring anyone).

>From "diskpart (8)":
     The disk partition sizes are based on the total amount of
     space on the disk as give in the table below (all values are
     supplied in units of 512 byte sectors).  The `c' partition
     is, by convention, used to access the entire physical disk,
     including the space reserved for the bad sector forwarding
     table.  In normal operation, either the `g' partition is
     used, or the `d', `e', and `f' partitions are used.  The `g'
     and `f' partitions are variable sized, occupying whatever
     space remains after allocation of the fixed sized parti-
     tions.

>From "bad144 (8)":
     Replacement sectors are allocated starting with the first
     sector before the bad sector information and working back-
     wards towards the beginning of the disk.  A maximum of 126
     bad sectors are supported.  The position of the bad sector
     in the bad sector table determines which replacement sector
     it corresponds to.  The bad sectors must be listed in
     ascending order.

     The bad sector information and replacement sectors are con-
     ventionally only accessible through the ``c'' file system
     partition of the disk.  If that partition is used for a file
     system, the user is responsible for making sure that it does
     not overlap the bad sector information or any replacement
     sectors.

I want to use use the "c" partitions of my disks for form one large file
system per disk.  If this is not acceptable, I will be resizing the
default partition sizes to better fit my needs.  Here are my questions:

1.  Under 4.2, are there advantages/disadvantages to one large file system
versus many smaller file systems?  What about quotas and file system
efficiency?  My understanding is that small file systems are a relic
of 16-bit machines which could only handle 64k inodes per file system.

2.  If I use the "c" partition, how do I account for/leave enough space for
the bad sector information and replacement sectors?

3.  If I resize the partitions, how do I account for/leave enough space for
the bad sector information and replacement sectors?

4.  This may be a silly question, but I can't figure it out.  The background
info above says that you can access the bad sector information and 
replacement sectors only through the "c" partition.  Well, if I do a disk-
to-disk copy using the "c" partition, am I copying one disk's bad sectors and
bad sector information to the other disk?!

I would appreciate any help I could get on this matter.  Thanks in advance.
You are to be congratulated for reading this rather lengthy message.

Steve Burinsky
smb at mimsy



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