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From: GWB on 23 Sep 2006 11:26
Claudio Lapilli wrote:
> and I also have non-branded (generic!?) cards that work fine, but I
> recommend getting good quality cards. The extra cost is worth the
> reliability, in my case I had a (Kingston) card permanently inserted in
> the calculator since december 2003, no problems so far either logically
> or by physical wear out of the contacts.

Having received my HP-50G only two days ago, I have very little
experience regarding this. However, a brandless 64-MB I had at home
didn't work right: after testing and formatting it on the calculator, I
could neither copy or purge files on it. After being formatted to
FAT-16 on the computer, I could copy files onto it but any attempt to
purge a file freezed the calculador. Using this card, I've been able to
succefully upgrade to the latest ROM though.

I guess any good brand SD card should work fine, but just in case I
decided to purchase a 128-MB SandDisk SD card (SDSDS-128-A10) which
works flawlessly. Too bad they're rather expensive here (Curitiba,
Brazil): about US$ 29.80. Considering I paid $25 for that 64MB card two
years ago in Paraguay and $60 for a used TDS 512MB for the 48GX years
ago, $30 for a 128-MB card looks almost like a bargain...

Gerson

From: Steen Schmidt on 23 Sep 2006 12:36
GWB wrote:

> [...] and $60 for a used TDS 512MB for the 48GX
> years ago[...]

That should be 512 *kB*, right?

Cheers,
Steen
From: GWB on 23 Sep 2006 15:42
Steen Schmidt wrote:
> GWB wrote:
>
> > [...] and $60 for a used TDS 512MB for the 48GX
> > years ago[...]
>
> That should be 512 *kB*, right?
>
> Cheers,
> Steen

You're right, my mistake!

And 512KB + 128KB built-in adds up to 640KB, which "ought to be enough
for anybody" :-) (At least it was for me: still 144K left on the
card)

Regards,

Gerson.

From: Veli-Pekka Nousiainen on 23 Sep 2006 17:03
GWB wrote:
> Steen Schmidt wrote:
>> GWB wrote:
>>
>>> [...] and $60 for a used TDS 512MB for the 48GX
>>> years ago[...]
>>
>> That should be 512 *kB*, right?
>>
>> Cheers,
>> Steen
>
> You're right, my mistake!
>
> And 512KB + 128KB built-in adds up to 640KB, which "ought to be enough
> for anybody" :-) (At least it was for me: still 144K left on the
> card)
>
> Regards,
>
> Gerson.

I would have not noticed even 512GB....
:-)


From: James M. Prange on 24 Sep 2006 00:48
...Zeno wrote:
> In article <1158943267.505366.106990(a)i42g2000cwa.googlegroups.com>,
> <no5software(a)gmail.com> wrote:
>
>> I never used such cards in my life , i see there are micro ( or mini )
>> versions, and "normal" versions. which one fits in the hp49g+ ? about
>> the different sizes, i think 256 is good right?
>>
>> I also read about FAT32, FA16, will i have to configure that?
>> any opnion on the sd reader i should buy?
>>
>> thanks, sor for the ignorance on the subject :O)
>>
>
> I have seen postings on the internet that some have had trouble geting
> the calculator to read SD cards tht were not the sandisk brand...I
> myself tried to uo use a Panasonic branded SD card that i had and it
> would not read it, but when I used a SanDisk branded one with the same
> calc it worked fine.
>
> In other words, use only Sandisk branded cards to play it safe.. I do
> not work for Sandisk, just know from personel experience they are
> better.

As others have written, it doesn't seem to me that there's any
need to get an expensive card or any particular brand.

I've tried a variety of MMC and SD flash cards (mostly used,
purchased at very low cost through eBay) branded SanDisk, Super
Talent, Viking, pqi, Delkin Devices, Nokia, Samsung, and 8MB and
16MB cards without labels. Of course the labeled brand name
doesn't necessarily match the manufacturer.

A few of the used cards arrived with various "disk" errors, but
after getting them formatted correctly, the only cards that I've
gotten that don't work just fine are a couple of used Samsung 32MB
RS-MMC cards thrown in as extras with an eBay lot. Those seem to
work perfectly if inserted after the 49g+ is already on, but it
won't power up with the card already inserted, and even after
removing the card, a "paperclip reset" (or briefly removing a AAA
cell) is required to turn it on. Those two cards do seem to work
perfectly in a card reader attached to my PC.

So there might be particular card models that the 49g+ just won't
work properly with, but I certainly wouldn't say "use only
SanDisk", or even "don't use Samsung". A brand name may have
design changes from one batch to another, or even outsource to a
different manufacturer, so many "good" cards of one brand don't
prove that that brand will always work, and a few "bad" cards of
one brand don't prove that cards of that brand will usually fail.

I suspect that a card sold for a particular device might come with
a special format, so if the calculator won't read it, try
formatting it and then try in the calculator again. If it still
doesn't work and it's under warranty, ask for a refund or
replacement.

That said, there have been reports of fake "high capacity" cards.
As I understand it, these cards appear to accept a file size up to
(or maybe even over) the labeled capacity, but don't necessarily
store the entire file. If you get a "cheap" card, then it would be
wise to try storing large files on it until you get a "disk full"
error, and also check that they can be read back correctly.

Of course someone could also simply change the label on a card to
indicate a larger capacity, so you'd get a "disk full" error if
you tried writing more than its actual capacity to it.

Note that for "mass storage" devices, including these cards, a
"MegaByte" commonly means 1,000,000 bytes, not 2^20 (1,048,576)
bytes. Also, some capacity is used up by formatting, and for SD
cards, some capacity is used up by the "security" area. For more
information regarding available capacity as reported by an
operating system compared to labeled capacity, see:
http://www.sandisk.com/Assets/Categories/Products/sd_capacitydisclaimer.pdf

The read and write speeds of the cards do vary, and as Steen
wrote, the formatting can make a big difference in the length of
the delay from pressing ON to actually seeing anything displayed.
My experience is that formatting with larger (and therefore fewer)
clusters results in a shorter delay. My understanding is that the
calculator reads the entire FAT when it turns on to determine the
available capacity of the card; the larger the FAT, the longer the
delay. For a worst case example, format a higher capacity card
FAT32 with 512-byte clusters.

I'm satisfied enough with a FAT16 formatted card, although that
means that, typically, more capacity will be wasted as "slack
space". Other limitations of the FAT16 file system include that
the root directory has a limit of 512 entries (and be aware that
"long" file names use more than one entry each), and a FAT16
volume can have a maximum of "only" 65518 files, not including
"0-byte file" directory entries, but counting subdirectories as
files.

Note that if you format the card with the calculator, then the
calculator determines which file system (FAT12, FAT16, or FAT32)
and cluster size to use, based on the card's capacity. What the
calculator decides is "best" for a particular card may or may not
suit your preferences. If you want more control over the format,
then use something else to format the card.

The calculator can use one partition of a card formatted like a
hard disk with a master boot record, but for use with only the
calculator, there's no advantage to having the card partitioned. I
prefer formatting it without a "master boot record"; just a "boot
record", like a floppy disk.

Most users won't really need a particularly large card for the
calculator, although I suppose that some might want one for large
graphics files, text files, and so on. After all, as far as I
know, the lowest capacity these cards were ever made in is 8MB; do
you really need more than that for the files that you want
available in your calculator? My advice is to look for a
reasonable price for a card for the calculator, and don't concern
yourself too much with the capacity. If you want a card for use
with another device, then get another card rather than sharing a
card with the calculator; these cards, especially in the lower
capacities, aren't all that expensive.

Now that I've mentioned "large" files, note that the size of the
files that the calculator can actually read will be limited by the
amount of available "System RAM".

Regarding speed, note that there must be limits to the
calculators' read and write speeds, regardless of the card's
speed, but I don't know what those limits actually are.

A card's read speed is normally highe
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