DS2 SD Card Copied to Larger SD Card File Size Grew
The SD card I use in my DreamStation 2 was an old 1GB slow card which worked OK, but was slow loading into OSCAR, so I thought I'd try a newer, faster 32GB Sandisk card. I quick formatted the new Sandisk card and simply copied the folder 'P-SERIES' from the old card to the new Sandisk. Looking at the properties of both the size is more than double on the new Sandisk card. The new Sandisk card is read by OSCAR OK, so I assume it will work in the DS2 tonight.
Any ideas why the bytes on the new card more than doubled? Does the DS2 use some kind of data compression which copied over as uncompressed?
I'll post tomorrow as to whether the DS2 wrote to the new card successfully.
![[Image: sArcsqG.jpeg]](https://i.imgur.com/sArcsqG.jpeg)
RE: DS2 SD Card Copied to Larger SD Card File Size Grew
Don't assume your CPAP will read and write to the card. It is totally dependent on the allowable format structures written into the CPAP's firmware. Your computer can read and write to a 256GB SD card, but the same card would totally be out to lunch in your CPAP.
- Red
RE: DS2 SD Card Copied to Larger SD Card File Size Grew
I haven't looked at how many files are created when I move an SD card from the ResMed to the computer but I assume there are a few, more than one in any case.
The old 1 GB SD card has small cluster sizes (the minimum unit of space allowed for data) and the new card has clusters which are either 4 or 8 times larger and two different files can't share one cluster. The idea of "used space" isn't necessarily data, it's more like "not available to be used by other files".
What you didn't show is how much data is used for each file (e.g. in Windows Explorer) which is likely the same on both cards. The remaining space on the SD card is a function of how existing files are written to the card. A copy of identical data files (or executable files or media files) is not going to become larger due to where it is.
In other words, copy a 3.5 MB photo file to each card. In Windows Explorer they will each be 3.5 MB files. The remaining space for other files won't be the same ratio of file/total capacity.
