multi-record file

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Let me begin by describing my problem. I am building a remote
flash-disk (FAT12) based embedded system for recording data. The data
recording events are initiated by the user who will communicate with
the recorder using TCP/IP. It has been decided that we'll use a single
file to record all the data. The problem is however that when we want
to retrieve data, we dont want to retrieve the entire file but rather
a list of a all recordings in the file. From this list I then want to
select which recording I want to retrieve.

I have thought about doing this in much the same way as a FAT. I want
to create one large flat file which I'll split into data clusters. I
then in the same way as writing to a hard disk, want to write the data
to these clusters. When I read and search through the records, I want
to be able to read the records and then return only that which I want.
This is a sort of "virtuall FAT"  I suppose. For now I need to be able
to do only recordings and then recall a specific recording if needed.

My problem is however that I dont know where to start. Is there anyone
out there who's done something similar or could anyone point me to
some info which might be usefull?

Kind regards.

Re: multi-record file

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This sounds like a conflict between goal and design, to me.  Why
invent a second, FAT-like layer, when you've already got a FAT
book-keeping system right there in front of you?

With the given usage in mind, the decision to do it all inside a
single, flat file contained on a FAT filesystem seems

Hans-Bernhard Broeker (
Even if all the snow were burnt, ashes would remain.

Re: multi-record file
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Look up the source code for the LBR format, extensive used on CP/M
systems.  The utilities used include lu and lar.  These were
written in C, and are available.  The format is defined in LUDEF5
(.htm).  You probably aren't interested in sources in assembly
language.  Get thee to google.

"I'm a war president.  I make decisions here in the Oval Office
 in foreign policy matters with war on my mind." -         Bush.
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