FAT vs FA32 SD format in the HP50G
Dueño de Monte
Since I have being in the forest I notice a change on my HP50G. ROM
2.10 U.
After left "civilization" I format my brand new SD card (SandDisk 2.0
GB) with the Pc (Windows XP Service Pack 2 etc) with FAT32 function,
and notice there is a 2-3 second delay when I turn it on.
I understand there is a reading of the SD card when I turn the HP50G
on, but this take long time if you compare it with the FAT format that
turns on almost instantaneously.
Why is this big difference ? The SD card has the same access speed
with FAT or FAT32 formats? This is just a little anoying, but the
first time I saw it I got scared, I thoguth there was something
wrong !.
So, thanks for your assistance, I am just formating the SD with FAT
function, and hope I am not loosing anything important.
Daniel.
TW
> function, and hope I am not loosing anything important.
Nope. FAT32 makes more clusters and is slower to read. . . hence the
delay.
TW
Irl
... google FAT16 FAT32 for more info. The FAT16 (what you probably are
calling FAT) supposedly is OK for disks up to 2GB, so your new card
might work with that format. Formatting it on the HP is probably more
reliable than on the computer, especially if you aren't sure how to
get to the controls on the formatter to specify FAT16 rather than
FAT32.
Irl
JYA
On 2007-11-17 00:47:40 +1100, Irl <ir...@mindspring.com> said:
> ... google FAT16 FAT32 for more info. The FAT16 (what you probably are
> calling FAT) supposedly is OK for disks up to 2GB, so your new card
> might work with that format. Formatting it on the HP is probably more
> reliable than on the computer, especially if you aren't sure how to
> get to the controls on the formatter to specify FAT16 rather than
> FAT32.
> Irl
the issue isn't about how big a card can be with fat16 ; but cluster
size. calculator files are tradiotionally very small ; so fat16 isn't
approprite for storing a lot of tiny file
the hp will format a card using FAT16 if the case is <= 32MB ; FAT32 if
it's more
--
They who would give up an essential liberty for temporary security,
deserve neither liberty or security (Benjamin Franklin)
barro
Also, the format command can be used from the PC with good results,
but a parameter must be supplied.
FORMAT H: /fs:FAT32 or /fs:FAT (H=drive letter). From PC, cluster size
can be specified using paramter, i.e. /f:512 for 512 bytes per
cluster.
JB
Paul Schlyter
JYA <nos...@nospam.blah> wrote:
> hi
>
> On 2007-11-17 00:47:40 +1100, Irl <ir...@mindspring.com> said:
>> ... google FAT16 FAT32 for more info. The FAT16 (what you probably are
>> calling FAT) supposedly is OK for disks up to 2GB, so your new card
>> might work with that format. Formatting it on the HP is probably more
>> reliable than on the computer, especially if you aren't sure how to
>> get to the controls on the formatter to specify FAT16 rather than
>> FAT32.
>> Irl
>
> the issue isn't about how big a card can be with fat16 ; but cluster
> size. calculator files are tradiotionally very small ; so fat16 isn't
> approprite for storing a lot of tiny file
Actually, the issue here is the number of clusters on the disk. FAT16
numbers the clusters with a 16-bit integer, which means it can
distinguish between 65536 different clusters on the disk. Some bit
patterns are reserved thouch, so in practice it's a little bit less
than max 65536 clusters. So the relation between disk size and cluster
size for a FAT-16 disk becomes:
Disk size Cluster size
32 MB 512 Bytes
64 MB 1 kByte
128 MB 2 kBytes
256 MB 4 kBytes
512 MB 8 kBytes
1 GB 16 kBytes
2 GB 32 kBytes
Now, any file on the disk with file length larger than zero must
occupy at least one cluster on the disk. So if you want to store,
say, 123 bytes of data on a 2 GB FAT-16 disk, this file will
occupy 32 kBytes on the disk. Only 123 bytes are actually used
and the remaining 32645 bytes are just wasted.
The HP48/49 files are usually quite small - a few hundred bytes or so,
perhaps one or a few kBytes at most. So if all your HP48 files are no
larger than 2 kBytes each, and if you have a 128 MB SD card, you can
at most store some 65536 files on that card. If you think that's not
enough, and you switch to a 512 MB SD card, FAT-16 formatted, you can
still store at most some 65536 files on that card. This is a little
bit of a paradox: even though you switched to an SD card 4 times larger,
the HP48 can still not store more files there!!! Anyway, that's how
FAT-16 formatted SD cards (or other mass storage units) works.
> the hp will format a card using FAT16 if the case is <= 32MB ; FAT32 if
> it's more
--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/
John H Meyers
> the issue isn't about how big a card can be with fat16,
> but cluster size. calculator files are traditionally very small,
> so fat16 isn't appropriate for storing a lot of tiny files
On the other hand, few people will ever be able to fill
the huge amount of space with calculator files,
on even the smallest SD card that's now found in a store.
The only way that I have even begun to make use
of the oceanic capacity of my cards is to store
all the ROMs and all the manuals on them;
of course, the calculator itself can't make use
of the manuals, but it's just a handy way
to carry them around with the calculator,
ready to pop into the nearest computer :)
> the hp will format a card using FAT16 if the card is <= 32MB,
> FAT32 if it's more
And the 49G+ thus originally formatted most cards using FAT32,
which it couldn't then even read for a ROM update :)
I've either left my cards as they came (all were FAT16),
or re-formatted them to the same specs, and also
keep my non-calculator (or obsolete archive) files
in subdirectories on the card;
as a result, calculator starts fast, and so does Filer.
[r->] [OFF]
John H Meyers
> FAT16 numbers the clusters with a 16-bit integer, which means it can
> distinguish between 65536 different clusters on the disk. Some bit
> patterns are reserved though, so in practice it's a little bit less
> than max 65536 clusters.
> [So any card can] still store at most some 65536 files on that card.
Yes, but there aren't that many files in the entire "hpcalc" site :)
The Filer will bog down, speed-wise, with even a very modest
number of files in the root directory, so you'd in any case
better put almost all of those 65,000 files into sub-folders,
or you'll never be able to use your card at all :)
If you do ever find a need for more calculator files on one card,
just develop a "Zip" archiver for the calculator,
which neatly solves similar issues on computers
(except that the basic "zip" format is itself limited
to 65,536 internal files per zip, and thus at most
4,294,967,296 zipped files per card -- but that averages
to 0.5 bytes per file on a 2GB card, anyway,
so you probably won't bump against that limit, either :)
[r->] [OFF]
John H Meyers
"Welcome to hpcalc.org (http://www.hpcalc.org),
the premier source of software for and information
about the HP50, HP49, HP48, and HP28 RPN programmable
graphic calculators and the HP38G, HP39, and HP40
programmable graphic calculators,
with 6512 files by 1986 authors and 1792 screenshots
totaling 639.29 MB"
So that's only 10% of the maximum number of files
that a FAT16 volume can hold.
If your 2GB FAT16-formatted SD card can hold all this,
I wouldn't worry about filling it up
with your own personal calculator file collection,
but it might be a problem, after all,
if you try to install a complete Windows and/or Linux distro
on the calculator, with only that SD card for storage.
Are there any plans for a CD/RW or DVD/RW expansion add-on?
(and can it be powered from the USB cable?)
[r->] [OFF]
Dueño de Monte
Daniel
P.S. maybe is too big for a simple calculator.