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Notes about copying RomWBW format media between device types


It is one of the design goals that block storage devices (not floppies) have identical disk formats for IDE, SD,...

I noticed an odd limitation to the use of "Win32 Disk Imager", when using it to manipulate these images.

I started with a Memory Technology Inc 2GB Compact Flash digital memory card (CF). It was formatted with MULTIFMT for 200 logical units. There was space for more but that was enough for me.

Over time I used approximately the first 35 logical units for various backups and reference copies of various software, editors, compilers, and utilities, including the development area for my apps.

Once the SD adapter on my N8-2312 was working (Thanks Wayne), I wanted to copy the contents of the compact flash chip to an SD chip so I could move my persistent storage to the very convenient on-board
SD adapter.

I used "Win32 Disk Imager" to read the contents of the compact flash chip, with the intention of writing it back to the SD chip. When I tried to write the file back to a fresh SanDisk CD card 2G, the imager complained there wasn't enough room on the SD for the image from the CF. In the diagnostic error message, it appeared that there were just a few fewer sectors on the 2GB SD chip than there had been on the 2GB CF.

My recourse at this point is to work around it and use a larger chip than I need, but which is large enough for the CF image. It occurs to me I could get around this perhaps by using "dd" on a *nix box, and I haven't tried that yet.

This was unexpected, and I wanted to share this experience with you so you can consider this before you waste time
over this.

One other thing I want to mention about the workaround is that if I attempt to clone this SD back to a CF, it will have to be nominally larger or the same size as the source SD, which is already slightly less than twice the size desired.

We may want collect specifications on CF and SD chips regarding number of sectors so we can be more proactive about choices regarding media size. Since RomWBW only fully supports 2GB media at this time, use of a 2GB chip
was efficient and financially sensible.

Douglas Goodall