[Oberon] FPGA - Save / Restore OBERON.FS

Chris Burrows chris at cfbsoftware.com
Fri Apr 21 16:27:10 CEST 2017

> > From: Skulski, Wojciech skulski at pas.rochester.edu
> > Sent: Thu Apr 20 06:42:54 CEST 2017
> > My biggest concern about Oeron FS is its limited size.

What do you plan to do with the Oberon filesystem that makes the size a
problem? The solution might not necessarily be to increase its size. For

My primary Project Oberon-related task is to support its use in embedded
software applications. The size of the file system could be an issue when
performing high-speed data logging. However, the Project Oberon, FAT and
other general-purpose filesystems were not designed for this sort of
realtime operation. Simply making the filesystem larger is likely to make it
even less suitable. 

Fortunately, an additional special-purpose filesystem can be readily
implemented for this task if we limit the requirements to what is necessary
and sufficient. 

To avoid data loss during realtime operation we need efficient code and fast
and predictable disk access speeds. SDHC cards (as with most other file
storage systems) are significantly more efficient when accesses are
sequential rather than random. Hence, the proposed requirements are:

1. On the embedded system the filesystem is write-only.
2. Disk writes are purely sequential.
3. Unlimited free space beyond the first 320MB of an SDHC can be used. 
4. Larger file sizes is a higher priority than the number of files.
5. Multiple files can be created but all the space could be used by a single
file if required.
6. Only one file can be open for writing at any one time. 
7. Once a file is closed it cannot be written to again.

Software would be written to transfer the files directly from the SDHC card
inserted into a PC for processing and analysis. The PC would also be used
for file deletion and other disk maintenance operations.

If anybody has a use for such a facility I would like to know if, and why,
any of the above requirements would be too restrictive for your use,

Chris Burrows
CFB Software

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