Re: LZ: TI storage...


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Re: LZ: TI storage...



When it came to Re: LZ: TI storage..., Tony Lieuallen thought:

> marco@magenta.com wrote:
> > I don't quite remeber this being discussed, but what's wrong with
> > using conventional volatile RAM?  Would it be all that hard to use
> > a 10 buck stick of 30-pin dram (1-2 megs) with a backup battery? 
> > If someone could work it out economically, it would be a great
> > system (small, inexpensive, fast, and widely available). 
> > Incorporate it with a backup battery (such as the lithium found in
> > the calc) as well as the main 9v, it would be great.
> > 
> > Of course, someone tell me if I'm full of crap too. :)
> 
> Yes, it would be that hard.  There is A LOT of circuitry required to
> access a simm, and it's a lot more complicated than simply hooking
> up a battery to keep the data alive.  Believe me.  It would kill the
> battery pretty quick, anyway.

Yeah, a simm would be basically impossible to utilize, at least a 
standard DRAM one.  DRAM must be refreshed very frequently (not sure 
of the number, but many times per second).  SRAM would be possible 
(not available as a simm AFAIK, but thats fine), but it would still 
be a pretty big drain on the battery, especially a large amount of 
it.  And if you ever looked at Mel's first version of the expander 
schematics, they were pretty complicated.  You'd need somthing like 
that to access a regular memory chip of any type.  But Flash ROM and 
EEPROM are available in a serial-access format, making them 
semi-usable with the linkport.  Thats how Mel was able to make the 
Expander SF circuitry so simple.

Ben Shakal
shakalb98@jhs.net
shakal@ns.net
Quote of the Month: "Despite the high cost of living, it remains popular."