Tim said:
Remember, originally DOS was largely a clone written to mimic the CPM
operating system API. In the subsequent OS wars CPM lost out to DOS,
which was a great pity as by then CPM was a much better multi-tasking
system, which DOS was not. Trying to do multi-tasking on top of single
tasking Dos, was a problem.
Windows today can still be used with FAT formated disks which is what
the CF camera cards look like, but the prefered file system is NTFS,
which is a huge improvement, especially for database management and more
secure transactions for financial institutions etc. NTFS is supposedly
more similar to Vax VMS, as the primary architect also designed VMS, but
I don't actually know. Using FAT on cf cards etc is a typical pragmatic
choice of simplicity and lowest common denominator compatibility.
Remember even Apple had to read floppies from PC's and had to interface
to ATA drives, so there exsisted expertise in dealing with FAT style
software and hardware interfaces for most platforms.
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Few people know or remember but OS/2 1.0 was essentially a virtual
memory, multi-tasking DOS designed to take advantage of the Intel 286
architecture. Too bad IBM and Microsoft killed it by pre-announcing
OS/2 1.1 with its GUI. Had OS/2 1.0 been allowed to ride for awhile as
a non-GUI OS it probably would have supplanted DOS as it was originally
intended to do and a more robust DOS design would still be available.
While I would never recommend FAT (File Allocation Table) or FAT32 (FAT
for disks larger than 2 or 4 GB*) for controlling a really large general
purpose file system, when reading and writing sequential (or near
sequential) files on a modest size storage device, FAT & FAT32 actually
have superior performance to the more sophisticated and overhead bound
file systems such as HPFS. Except for occasional deletions, digital
photos on a CF or other flash storage device are sequentially stored,
sequential files for which FAT is perfectly well suited.
Dave Cutler of Digital Equipment Corp. was the unnamed VMS architect who
was hired away from DEC to work on the design of Windows NT and the NTFS
file system.
* The architecture of the FAT file system allowed up to 4 GB disks.
Only Windows NT, however, actually supported a 4 GB FAT disk size.
Earlier implementations are limited to 2 GB. FAT32 raises the disk size
architectural limit to 8 terabytes but the implementation sizes may be
much smaller. Generically, when people refer to FAT they are really
referring to FAT16. The original FAT is also known as FAT12 which was
used for disks smaller than 16MB. (remember when that was big?)
Chuck Norcutt
former PC-DOS and OS/2 Integration & System Test mgr... who wuz there
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