21 Jul
2014
21 Jul
'14
8:34 a.m.
On Mon, 21 Jul 2014, Jules Richardson wrote:
Interesting... I didn't realize that it was
possible to go beyond the 2GB
limit and for things to still work - I always assumed that normal file ops
would break at that boundary, even if a >2GB filesystem was hand-crafted.
In general, with few exceptions, you can not go bast 2G, because MOST of
the programs also used a 32 bit SIGNED number. The 2G limit applies not
only to drives, but also to the FILE SIZE in FAT16.
However, in NT4?, FAT16 CAN go up to 4G (4G minus one byte for
nit-pickers). That can, of course result in nasty incompatabilities
between NT4 and other products for any drives (or files) between 2G and
4G.
To waste a little time: step on the DIRectory sectors of a floppy. Take
the last 4 bytes of one of the FPDEs and change it to FF FF FF FF, and see
which versions of DOS and programs say that the file size is -1 byte.
Change another one to 80 00 00 00 to get -2147483648. Copying a file of
negative size to a disk fails to increase the free space.
BTW, I am using "logical" "drive" to refer to MS-DOS's
presentation of a
partition as if it were a disk drive. I am not referring to the various
types of drives and partitions. Thus, I am referring to splitting a 4096
into two 32M and one 16M as creating three "logical drives". I don't
remember when Microsoft began support for durther divisions, and
again altered the terminology.