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HP 50g & SD Cards: Performance, Format, Notes
09-09-2016, 10:33 AM (This post was last modified: 09-09-2016 10:36 AM by JDW.)
Post: #109
RE: HP 50g & SD Cards: Performance, Format, Notes
Regarding the Turn On DELAY, my 256MB SD Card, formatted inside my 50g, now causes the 50g to take 1sec. for the display to appear after pressing ON. To confirm why I put the SD back in my iMac and ran the following command in the Terminal:

diskutil info /Volumes/NO\ NAME

("NO\ NAME" because I formatted it inside the 50g.)

The Terminal then displayed the following:

Device Block Size: 512 Bytes
Allocation Block Size: 2048 Bytes

So the 50g is slow to turn ON because the Allocation Block Size is too small for this 256MB card.

To reduce the slowness I reformatted the 256MB card via the Terminal using the following command line:

diskutil partitiondisk /dev/disk3 1 MBR "MS-DOS FAT16" "SD256MB" 0B

Then I ran the following line to confirm the Allocation Block size:

diskutil info /Volumes/SD256MB

The Terminal responded:

Device Block Size: 512 Bytes
Allocation Block Size: 4096 Bytes

With that larger allocation block size, the 50g now takes 700ms to display the screen contents after pressing ON. (To time it, I Googled "Timer" and used that timer, clicking Start at the same time I press ON, and then pressing stop immediately when the screen displays. I repeated the timer test 3 times to get an accurate measurement.)

Wanting a still faster turn-on time, I launched the Disk Utility app to UNMOUNT my SD Card (but kept it inserted in my iMac), and then I used the following Terminal command line to format the SD card with a larger Allocation Block Size:

sudo newfs_msdos -F 16 -v SD256MB -c 32 /dev/disk3

(Where the "-c" sets 32 clusters of 512 bytes each, 16k total.)

And then the Terminal reported:

Device Block Size: 512 Bytes
Allocation Block Size: 16384 Bytes

Using the Google timer, I now get an ON-time of 550ms. Hmmm...

New Topic...

For the very first time, I decided to try to copy User RPL code out of a forum post here and then Paste that code directly into TextWrangler on my iMac. I then saved the text file without a file extension to my SD card using these settings:

Line Breaks: Windows (CRLF)
Encoding: Unicode (UTF-8)

I then inserted the SD card into my 50 and viewed the content of my file with the File Manager. Here's a PHOTO of what I saw on the 50g's screen:

Garbled User RPL Code

And here is the code that I copied and pasted into TextWranger:

   #21d #8d BLANK "" 2 →LIST
   6 →LIST

I then repeated the above but this time using the following "escaped" code instead:

   #21d #8d BLANK "" 2 \->LIST
   6 \->LIST

But when I view the file on the 50g in File Manager, it looks pretty similar, except that I see the "\" characters. I still see the black squares. The only thing that's fixed is that I now see "->" instead of the 3 garbled characters.

What specifically am I supposed to do when saving User RPL programs using a text editor on a computer, saving the file to the SD card?
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RE: HP 50g & SD Cards: Performance, Format, Notes - JDW - 09-09-2016 10:33 AM

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