Sinclair QL-SD, Руководство пользователя

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QL-SD User Manual 19
smaller you make the group size for the same size of disk, the larger your map grows,
as there are more groups to keep track of. The larger you make it, the larger your slave
blocks grow (Groups are slaved together).
If you are tight on memory (maybe you only have 256kb memory extension), do not be
tempted to make your File system too large - You may end up with an unusable system
because all your precious memory might be used up by the QL-SD driver. A
recommended sensible setup for a QL with expanded memory would be a file system
size of 64MB with a group size of 8. Miracle x-Card owners can easily go for larger File
system sizes.
The most extreme case is with an unexpanded QL: Originally, we thought it wouldn’t
even work with QL-SD - But a Group Size of 8 and a file system size of 3 MB seems to
be the optimum working setup - Maybe it’s about time you consider expanding your
QL’s memory?
8.
QL-SD Driver S*BASIC Procedures and Functions
The QL-SD driver (EDDE 2 core) installs the following new procedures and functions into
S*BASIC:
·
SDC_START
· MOUNT
· UMOUNT
· SDC_USE
· SDC_BASE()
· SDC_VER$()
8.1.
SDC_START
Activates the QL-SD driver, in case activating it during the ROM initialisation sequence has been
aborted by a key press. If you simply boot your QL without pressing a key, you will hardly ever
need this command. The ROM will then activate the driver and mount the card in the drive.
SDC_START
takes an optional single Long Word parameter containing a bit field of flags and
configuration settings, one of which is bit 6 (
F_NATIVE_FS
) which, if set, forces the driver to look
for a native QDOS file system instead of a FAT32 image (We already told you we do not
recommend to use this mode, did we?).
SDC_START
also allows you to pass the starting LBA of an image file on the FAT32 card, and the
number of buffers to use, but this is for non-standard configurations and not further explained here..
Example:
SDC_START
Note that in current versions of the driver, repeated use of
SDC_START
when it is not necessary,
might waste QL memory by allocating unnecessary duplicated space for the disk map and sector