Macintosh: How System Heap Size Is Allocated (11/94)

1) Where is the heap size stored on a volume?

2) If I adjust a heap size on a volume and copy that System Folder to
another empty drive, will the boot blocks be set to the new modified
size?

The default heap size is stored in the boot blocks of a startup volume. For System Software 6.0.4 and System Software 6.0.5, the default size 128K.

Note: When the System Software 6.0.5 System Tools disk is booted on a Macintosh SE with 1MB RAM, the System heap takes up 188K of RAM. The default System heap size is used as a guideline; the heap size is increased, if necessary.

The boot blocks, including the default heap size, are taken from the source disk, unless that disk does not have a valid copy of the boot blocks or if it is a file server. In these cases, the boot blocks are taken from the "boot" resource in the System file being copied.

Article Change History:
28 Nov 1994 - Reviewed for technical accuracy.

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