Re: Need help updating ROM on 49G+
Message #7 Posted by James M. Prange (Michigan) on 4 Oct 2005, 5:48 a.m.,
in response to message #6 by James M. Prange (Michigan)
By the way, for those still using a ROM revision earlier than
2.00, the procedure above using the [ON]&[F4] keys is the only one
available on the calculator.
The 49g+ can use a "MultiMediaCard" (MMC) as well as a "Secure
Digital" (SD) card. Differences are that MMC card have a bit more
available capacity, lack the "lock" switch and a small notch on
the right side, have seven contacts instead of nine, and are 2/3
the thickness.
Of course the MMC also lacks the "security" features of the SD
card. These "security" feature are meant to limit the distribution
of copyrighted content. I don't know; maybe they could be used by
someone selling applications for the 49g+.
The SD card's lock switch position is ignored with ROM revisions
earlier than 2.00 (you can indeed write to a "locked" card), but
works as expected with 2.00 (attempting to store to a locked card
results in a "Disk Protected" error).
An MMCplus should work, but should
function as an ordinary MMC in devices (such as the 49g+) not
designed to take advantage of the extra I/O lines. Don't be
expecting the dramatic increase in speed from using one.
The smaller size cards are available pretty cheap on eBay,
although older cards typically seem to be slower. I expect that
even an "8MB" card would be plenty big for typical calculator
uses. But note that ROM 2.00 formats 8MB cards to FAT12, which it
won't read from or write to.
Regarding my "64MB" capacity MMC, here are some numbers that I've
come up with. Note that I'm treating 1MB as 2^20=1048576 Bytes
here, although the card manufacturers consider 1MB to be 1000000
Bytes. SD cards will have fewer total sectors available, because
some capacity is used for "security" purposes. The FAT16 boot
record was tweaked with a disk editor. For FAT16, the root
directory can hold up to 512 entries if the filenames all comply
with "8.3" all capitals DOS "short" file naming conventions; a
"long" filename directory entry is larger, thus fewer can fit in a
given directory. "Your mileage may vary."
Total sectors (unformatted):
125440=64225280B=62720KB=61.25MB
Formatted FAT16, 1KB clusters
Reserved sectors:
2=1024B=1KB~0.0010MB
Sectors per FAT:
244, allowing up to 62462 entries for clusters.
Sectors used in both FATs:
488=249856B=244KB~0.2383MB
Sectors used for (nominal) 512 entry root directory:
32=16384B=16KB~0.0156MB
Total sectors used up for formatting:
522=267267B=261KB~0.255MB
Sectores left for files (including subdirectories}:
124918=63958016B=62459KB~60.9951MB
1KB clusters for files (including subdirectories):
62459
Formatted FAT32, 512B clusters.
Reserved sectors:
32=16384B=16KB
Sectors per FAT:
973, allowing up to 124542 entries for clusters.
Sectors used in both FATs:
1946=996352B=973KB~0.950MB
Sectors used for (initial, 1-cluster) root directory:
1 sector: 512B=0.5KB~0.0005MB
Total sectors used up for formatting:
1979=1013248B=989.5KB~0.9963MB
Sectors left for files (including larger root directory and subdirectories):
123461=63212032B=61730.5KB~60.2837MB
0.5KB clusters for files (including larger root directory and subdirectories):
123461
I expect that it would be a long time before I maxed out this card
in terms of either total file sizes plus slack space or maximum
number of files, regardless of whether I format it FAT16 or FAT32.
Regarding the connectivity kit and USB driver on the CD-ROM, if
it's lower than Version 2.2 Build 2353 with USB driver Version
1.2, then remove them (if already installed) and imstall the
current versions instead.
Regards,
James
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