[dba-Tech] Software on a USB Drive

JWColby jwcolby at colbyconsulting.com
Thu Nov 16 10:24:25 CST 2006


Rocky,

Flash have faster access times than hard drives, but slower read/write
times.  IOW, the drive has to rotate to get the data under the head, which
can be milliseconds, but once the data starts to stream on/off the disk, it
does so faster than flash.  The other issue with Flash is that they can only
WRITE any given memory location a certain number of times before the
location "wears out".  Associated with this is the problem that flash is
written in pages, not individual bytes.  Which means that if only a single
byte of a page changes, the entire page has to be written anyway.

The question is, is this an issue?  It really depends on how the drive is
used.  Many files are written once and then stay there for a LONG time.
Word documents, excel spreadsheets etc.  OTOH, things like the area of a
disk used to contain data for a SQL Server or Access database might change
many times per second, just depending on usage of the database.

OTOH, flash is purely electronic vs. mechanical for hard disks.  Electronic
circuit failures group into two types, electrostatic and mechanical (yes
mechanical).  We all know the issue with ESD.  The mechanical failures with
chips come into play with the bonding wires that link the chips to the
external pins leading off the container.  These wires are made of gold, and
are finer than a human hair.  They will fail from flexing caused by heating
up and down as the chip is turned on / off.  You might have noticed that
incandescent light bulbs never seem to just fail once they are on, but
rather they fail (typically) when you turn the light bulb on.  Incandescent
lights are a hot wire.  The wire flexes as it heats up and the metal wire
expands.  Eventually that flexing causes a stress fracture.  The same
phenomenon occurs in electronic chips, though much slower simply because the
heat is usually less so the amount of flexing is less.  Unfortunately
neither of these failure types is the issue with FLASH "max write cycles".

Anyway... If electronic chips were never turned off, and never subjected to
ESD, they would likely last for centuries, or perhaps "forever".  

The reality is that rotating and solid state memories both have their uses
and the boundaries of where each is most useful shift back and forth but
both will be around for awhile.

There are other "flash" (solid state) memories on the horizon though, based
on magnetics and the likes.  We'll have to wait and see how they effect the
equation.

You have heard that Vista can use FLASH for an intermediate level cache.

John W. Colby
Colby Consulting
www.ColbyConsulting.com

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Beach Access
Software
Sent: Thursday, November 16, 2006 10:48 AM
To: 'Discussion of Hardware and Software issues'
Subject: Re: [dba-Tech] Software on a USB Drive

True.  Can a 100GB flash drive be far off?  And at a price competitive with
a hard drive?  

Do you know anything about their reliability?  Ever hear of a flash drive
failing? And are the speeds of reading and writing comparable?  

The 8GB one I used seemed to generate a lot of heat.  I wonder if they will
degrade quickly from their own heat.

Rocky


-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of John Bartow
Sent: Thursday, November 16, 2006 7:37 AM
To: 'Discussion of Hardware and Software issues'
Subject: Re: [dba-Tech] Software on a USB Drive

You really have to want a lot of data in your pocket to spend that kind of
cash, eh?
:o)

Kind of a sign of times to come though. Pretty soon we'll be using solid
state storage instead of hard "disks" for our storage needs.

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Beach Access
Software
Sent: Thursday, November 16, 2006 12:26 AM

I see it now - $1500.  But I'll wait until next month when I can get the
$1400 rebate.

Rocky

_______________________________________________
dba-Tech mailing list
dba-Tech at databaseadvisors.com
http://databaseadvisors.com/mailman/listinfo/dba-tech
Website: http://www.databaseadvisors.com

--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.430 / Virus Database: 268.14.6/535 - Release Date: 11/15/2006
3:47 PM
 

_______________________________________________
dba-Tech mailing list
dba-Tech at databaseadvisors.com
http://databaseadvisors.com/mailman/listinfo/dba-tech
Website: http://www.databaseadvisors.com




More information about the dba-Tech mailing list