> Van: Eric Oliver <eric@KEDCOENT.COM>
> Aan: PICLIST@MITVMA.MIT.EDU
> Onderwerp: To C or not to C
> Datum: woensdag 3 februari 1999 15:43
>
> Hi guys,

Hello Eric,

<Snip>

  Not fair ! ;-)  I was just busy thinking about/doing the same, on a
somewhat smaller scale (no keypad, no LCD. no MAX232. Requests received
thru RS232), using 24Cxx I2C-memory (8 to 32 (64 ?) KByte variants).  Maybe
even leeching it's power from the RS-232 connection ...

> First, I plan to implement a very scaled down version of the DOS FAT
system
> in the NVRAM.  Master file table, FAT, sectors, and no subdirectories.
The
> user will not be aware of the storage scheme. I want to use it to
> facilitate memory reuse as data blocks are added, changed, or deleted.

Another way to link "sectors" together could ne done by adding a pointer to
each data-block telling where the next "sector" is.

By the way : with 2 (or 4) MB of space a Directory-structure would be handy
..

> Second, the user must be able to search for a "file name".  I thought I
> would take the approach the cell phone manufacturers used.  The user
enters
> a few characters from the beginning of the name by way of the numeric
> keypad and then uses the up and down keys to scroll through the list.
This
> may require maintaining an index in a reserved portion of the NVRAM.

If a standard DOS-type directory-entry will be used to store the file-names
there is room to add 2 pointers, one "up" and one "down", creating a
double-linked list.  An "insertion" routine could add a new file-name
anywhere, but by opdating the link-pointers make sure that the file-name
list stay's sorted.

Warning !  DOS Standard way's to communicate thru RS-232 ("TYPE {text} >
COMx" or "COPY {file} COMx") do not use handshake ...  And you will need it
(I think) when up-loading something to your device.  So, the first thing to
do is to load & install a "driver" for it ....

Greetz,
Rudy Wieser
caisson@telebyte.nl