- -- [ From: Man F Wong * EMC.Ver #2.3 ] --
Hi! My mailserver cannot send mail to the OGO mailing-list, so I'm sending
this directly to you. Feel free to forward it to the list if you like.
Frank Lyon Cox wrote:
> At 05:32 AM 6/05/1996 -0500, you wrote:
> >Could someone please explain the advantages and disadvantages (and just
> plain differences) of SRAM and Flash-RAM, please?
> >
>
> The main difference in my mind is that flash-RAM comes in much larger
> capacities and at a much lower cost per megaByte.
Also, flash memory stores data "permanently" and does not require battery
power to maintain its content, ie. it works like a hard drive on your PC.
OTOH, a SRAM card would always need a (battery) power supply beyond the few
minutes of self-sustenance one typically has. However, these are only the
pros for using flash memory.
The cons include significantly(?) higher battery drain and slower memory
access (both especially true w/ write operations). Because of its
"permanent" storage of data, its components do eventually wear out and fail
after many writes (much like a hard drive). I read in a recent Byte
magazine that today's flash cards are built to last ~10 years(??) of
average use (whatever that means), so that may not concern you.
> According to the ogo documentation, it is not compatible with Flash-RAM,
but
> I've seen information about Flash-RAM cards that come with drivers for
the
> ogo.
HP probably decided not to support flash cards because of their higher
power usage. Since they were marketing the Ogo as an "organizer plus", not
a palmtop computer or even a general-purpose PDA, they probably convinced
themselves that the higher capacities and cheaper cost of flash cards would
not benefit the _typical_ Ogo user enough to offset flash cards'
disadvantages. In fact, they discourage the notion of _file_ storage and
manipulation and don't even officially support the use of SRAM cards as
media for direct access of application data (only for application
storage/launching and data backup/retrieval). This indeed limits the
amount of extra storage most people would need. HP decided to use GEOS in
part for this very reason; GEOS can be customized to hide the use of a file
system, and GEOS and GEOS-based apps require much less memory to store and
run.
However, most techies (including myself) who tried out the Ogo have
apparently found it lacking in memory and may find SRAM cards too expensive
and (eventually?) a bit limited in capacity. Current commercial technology
produces SRAM cards at upto 4MB capacity (for mega$$$/MB!!) and upto 20MB
for linear flash cards (the kind that can work in the Ogo and most other
PDAs on the market). MagicRAM is the only official supplier of flash cards
w/ Ogo driver support that I know of although I've seen mention of Pretec
Electronics at one web page I recently encountered. I also considered
using MagicRAM, but I think I'll try a used SRAM card for now. They
typically cost about the same $$$/MB as flash cards, and MagicRAM charges a
bit too much for theirs (probably because they are currently the only
official supplier for Ogo's).
Anyway, hope this long-winded explanation is helpful to you.
_Man_