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Ivory Partition Icon on the Desktop

    Date: Mon, 12 Jun 89 09:32:31 PDT
    From: felix@Warbucks.AI.SRI.COM (Francois Felix INGRAND)

       Date: Sat, 10 Jun 89 15:00 EDT
       From: barmar@Think.COM (Barry Margolin)

	   Date: Fri, 9 Jun 89 15:16:48 PDT
	   From: Francois Felix INGRAND <felix@ai.sri.com>

	   But in the formatting/partitioning utility from Jasmine, I did not find
	   any way to make a partition invisible (except by not mounting it of

       In the 7.3 version, the FEP file system was in an ordinary Macintosh
       file, not a partition.  This is analogous to the relationship between
       LMFS and FEPFS -- a LMFS partition is a FEPFS file.


    I think it is still more or less true, as you can create more than one FEP
    file in one Macintosh partition. The only difference is that they now put
    these FEP files in a special partition.

    But what I wanted to do was to hide the partition itself... I tried with
    ResEdit, but there is no way to hide the partition icon and I do not see
    any easy way to do it.


Let me see if I can clear this up a bit ...

We haven't changed the implementation of Ivory partitions (FEP file
systems) in 7.4.  An Ivory partition is still an invisible file residing
in the Macintosh file system.

We did, however, change the recommended setup for disks in 7.4.  

We made this change because the Macintosh file system is inefficient in
its use of large disk drives.  This inefficiency is caused by the
relatively small size for the fields which represent the size of a file.
Therefore, on large disks, the granularity of file size increases.  For
example, on a 640MB disk, the granularity is 20 512 byte blocks.  Thus,
a file with only a single byte of data will occupy 10K bytes on such a
disk.  (Similarly, a file with 10K + 1 bytes of data will occupy 20K

To get around this problem, the Macintosh operating system allows you to
partition a disk into more than one Macintosh partition.  Each such
partition holds a single Macintosh file system or A/UX file system.  To
all but the lowest level software, a Macintosh partition looks just like
a separate disk drive.  Since each partition is smaller, the file size
granularity is also smaller which allows more files to be included in
the file system than would otherwise be possible.

Therefore, we suggest that the Ivory partition, hereafter called the
FEPFS, be placed in one Macintosh partition and a second partition be
used for Macintosh files.  In doing so, the partition used for the FEPFS
occupies the majority of the disk and has a large file size granularity
which doesn't hurt as there's only one file (the FEPFS) in the
partition.  The other partition is much smaller with a much smaller file
size granularity.  As a result, you can fit more Macintosh files in the
same amount of space on your disk.

The only drawback, if you consider it one, is that there are now two
disk icons on the desktop -- one for each partition.

Whether or not it's possible to make a Macintosh partition's icon
invisible is a function of the disk driver software used to format the
disk.  There's no general mechanism in the Macintosh operating system to
hide disk (partition) icons.  To my knowledge, no driver available today
provides the ability to hide partition icons.

  - Gary