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HP 50g & SD Cards: Performance, Format, Notes
07-16-2016, 03:06 AM
Post: #5
RE: HP 50g & SD Cards: Performance, Format, Notes
(07-15-2016 08:21 AM)JDW Wrote:  To those of you who own a 50g and use an SD card, I have 3 questions:

1. Does the SD card speed matter? Is there any discernible speed difference between the cheapest SD card available versus a fast card? (I am thinking about getting a 1GB card. I assume this is a better way to transfer to/from a computer than using USB connectivity (Hoppi/KERMIT), correct? I use a Mac.)
Card speed is much more than what the 50g can handle, therefore it doesn't matter. The 50g will clock the card at 20 MHz, which gives you around 2 MB/s of maximum sustained transfer speed. That's all you are going to get, no matter how fast is the card you use.
SD cards are the best way to transfer data to/from the calculator. There's no software to install so it's portable and reliable.

(07-15-2016 08:21 AM)JDW Wrote:  2. The HP 50g User's Guide says, "The HP 50g will only work with cards in the FAT16 or FAT32 format." but this HP Forum thread says, "If you place a new SD card into the HP 50g and it is not recognized, it should probably be reformatted under FAT16." This appears to be conflicting information. What is correct?
Older ROM versions only supported FAT16, later FAT32 was supported, so those apparently contradicting comments are probably taken from 2 different times.
The boot loader only works with FAT16, so in order to flash firmware to the calculator you'll need to have a FAT16 format, but for normal calculator operation either FAT16 or FAT32 work well.
For speed reasons, I recommend you use a smaller card (or a big card with a small first partition, you can create a second partition and use the rest of the card for non-calculator data).
50g creates very small files, so it will work best with a small cluster size (I'm assuming you are familiar with the FAT file system here). You'll get the optimum speed from your card when you use:
a) Smaller clusters
b) Small number of clusters.

If you have a big card (I'd say 1 GB is big), it will probably be formatted FAT32 with 4kbyte clusters. This will create many small clusters, and will make your calculator very slow to startup (it will take a second or more to wake up from OFF).
To reduce the number of clusters, you can format the card with larger clusters, and this will speed up your ON time, but now you have to write larger chunks of data for each tiny file, which slows down all your STO/RCL operations.
The ideal point is a reasonable number of small clusters, in other words, a smaller card or a card with a smaller partition.
I have a 64 MB card and hasn't filled up in 10 years.

(07-15-2016 08:21 AM)JDW Wrote:  3. Rather than key-in long text notes on the calculator, is it possible to save notes as a *.txt file via PC to the SD card, then insert the SD in the calculator and either use the notes directly off the SD or save them (STO) to internal memory?

Thank you.

Others have already replied to this one better than I can.
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RE: HP 50g & SD Cards: Performance, Format, Notes - Claudio L. - 07-16-2016 03:06 AM

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