> With all this talk lately about the serial RAM's...
>
> Why use a SERIAL ram in the first place ?
> They're much slower than the traditional parrallel
> memories and RAMTRON has parrallel FRAM's as
> well... so why bother ?

Let's look at some characteristics of common devices
[the "device" column is at the end of the table rather than the start to
maximize the likelihood that everyone's mailreader will handle the tabs
well.]

I/O     BOARD   READ    READ    WRITE   WRITE   GLITCH  DEVICE
PINS    SPACE   SPEED   ENDUR.  SPEED   ENDUR.  RESIST  TYPE
-----   -----   -----   -----   -----   -----   ------  --------------
None    None    Fast    Inf.    V.Slow  M's     V.Good  Int. EEPROM (16x84)
Many    Lots    Fast    Inf.    Fast    Inf.    Vol.    Parallel RAM
Many    Lots    Fast    Inf.    *1      K's     V.Good  Parallel flash
Many    Lots    Fast    Inf.    Slow    M's     V.Good  Parallel EEPROM
Few     Little  Medium  Inf.    Medium  Inf.    Vol.    Serial RAM
Few     Little  Medium  10G     Medium  10G     Fair    Serial FRAM
Few     Little  Medium  Inf.    Slow    M's     V.Good  Serial EEPROM
Few     Little  Medium  Inf.    *1      K's     V.Good  Serial flash

I/O Pins: Many==16-24 or more; Few=2-4
Board space: Lots==28 or 32-pin package; Little==8-pin package
Read/write speed: Fast==under 10us; Medium==10-1000us; Slow==over 1ms
  V.Slow==over 5ms; *1==medium except for page-erase cycle (over 100ms
  on some devices; over 2 seconds on others)
Read/write endurance: K's==10,000-1M (typ.); M's==1M-20M (typically);
  10G==10^10.
Glitch-resist: V.Good==power glitches and such are unlikely to cause any
  damage to device contents outside of current byte being written.
  Vol.==power glitches (or loss of power) may trash entire device contents.
  Fair==memory contents non-volatile but stray signals may cause memory loss
    (even while trying to READ the device)

Looking at the above table, serial RAMs are the only class of device which
combines the features (Few I/O; infinite read endurance; medium-speed write)
or (Few I/O; infinite write endurance).  For applications which demand either
of these feature combinations (or any of the others that serial RAMs uniquely
provide) serial RAMs are probably the best choice... if they can be found
anywhere...