Re: SRAM vs Flash-RAM

Marc DeVinney (devinney@charger)
Wed, 5 Jun 96 13:44:12 CDT

At a fundamental level, the difference between Flash and SRAM is in the silicon structure of the device. Without getting into details, SRAM only stores a charge (logic "1") for each bit while power is applied. In the case of a PC Card, a battery provides this power. As soon as the power is removed (or battery dies), the contents of the SRAM are lost and is therefore called "volatile" RAM.

For Flash, no power is required to maintain this charge and is nicknamed "nonvolatile" RAM. Since the Flash cell structure is much smaller than that of SRAM, the densities are higher and the result is lower cost than that of SRAM at the same capacity. The downside here is that more power is required to modify the contents of Flash than to read it. Since no battery is available (or required) on the PC Flash Card, this power is supplied by the host computer. If that host computer is an Ogo, this can significantly affect its battery life.

The FineBind Web page (http://www.axxis.com/~mfine) has a reference to some compiled information on power requirements for different PC Cards. This could be very valuable in deciding whether a product is appropriate for the Ogo.

MED.

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mailto:Marc.DeVinney@aud.alcatel.com

> From owner-ogo@lifelike.com Wed Jun 5 05:45:27 1996
> From: Bob Hall <rbhall@dallas.net>
> To: "'ogo@lifelike.com'" <ogo@lifelike.com>
> Subject: SRAM vs Flash-RAM
> Date: Wed, 5 Jun 1996 05:32:43 -0500
> Sender: owner-ogo@lifelike.com
>
> Could someone please explain the advantages and disadvantages (and just =
> plain differences) of SRAM and Flash-RAM, please?
>
> 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.
>
> Thanks in advance,
> Bob Hall
>