🚀 go-pugleaf

In article <1992Aug27.171032.14617@uwm.edu> anthony@csd4.csd.uwm.edu (Anthony J Stieber) writes:
>In article <fr-n==q.payner@netcom.com> payner@netcom.com (Rich Payne) writes:
>
>>This? Flash EPROM sounds interesting, but it still seems to me that
>>the voltage and power requirements to -write- to it are far above the
>>power requirements for a small drive. It would not seem that the present
>>FLASH EPROM would be a replacement for current small HD's. But I think
>>it still would be usefull. 
>
>Voltage isn't the same as power.  

Agreed, but voltages above that provided by the batteries requires
a DC-DC converted, which sucks power as well. So for portable devices,
power delivered will not equal power consumed for voltages above the
battery voltage. 

>                                      The 4MB card consumes 0.15 watts
>active, and 0.04 watts standby.  

By active, do you mean reading, writing, or both?

>                                  The main problems with Flash EPROM are
>that it takes on the average 2 seconds to erase a 256KB zone.  

Can several zones be erased simultaneously? Does this increase power
consumption? And how does the file system do small writes without
erasing other files? Does it require 256K of cache, and if so will
this not increase write times by the amount needed to load/read the
cache?

>                                                                    The
>entire zone must be erased.  Once erased, writes take 10us per byte and
>reads are 200ns maximum, data transfer at 8MB/s.  The card can be shut
>down between accesses so it takes no power, then be instantly powered
>back up.  A disk drive will take a few seconds just to spin up.  Disk
>drives also have head and rotational latency.  Note that all the figures
>I have are for 4MB cards, 20MB cards may differ significantly.

Hopefully by being improved. :^)
 
>I could certainly see a 20MB Flash card replacing a Kittyhawk or
>similar drive in at least some applications.  Simply by size and power
>consumption, two or more 20MB cards would fit where only one hard drive
>would.  They may end up more complementary that competitive however.
>Even a drive as small as the Kittyhawk could probably have a few
>megabytes of Flash memory for use as cache.  This could give the low
>power and speed of Flash with the low cost of disk.
>
>--
><-:(= Anthony Stieber	anthony@csd4.csd.uwm.edu   uwm!uwmcsd4!anthony
>

Rich

payner@netcom.com