[squeak-dev] Re: Smalltalk and flash memory

Louis LaBrunda Lou at Keystone-Software.com
Sun Jun 8 20:50:44 UTC 2008

Hi David,

>Your comments about not having to intentionally manage writes of objects
>indicates that you believe that the read/write/erase characteristics of
>flash memory are similar to  conventional memory.  Cells in flash memory
>can't be re-written without first erasing.  Erasure occurs on block
>boundaries.  You can only erase a block a certain number of times (typically
>in excess of 100,000).  I find it convenient to think of flash as a very
>fast replacement for disk drives.  Compared to disks, it has very fast read
>access, especially for random reads, but the block structured erase/write
>protocol look more like a disk drive.  See
>http://en.wikipedia.org/wiki/Flash_memory for more.

I am being a little sloppy calling the persistent memory I'm talking about
"flash memory".  I of course don't mean the exact kind of flash memory used for
memory sticks or disk drive replacements.  You are correct about their block
nature and that is clearly not what I want.  NOR flash memory is what I am
talking about.

Maybe I'm looking too far into the future but NOR flash memory is here today and
I think the prices are coming down.  I would like to generate a conversation
that might show a need for this memory and motherboards that support it, sooner
rather than later.

>Object persistence managers like GemStone, Glorp, etc, are still needed, but
>flash memory will definitely change the way we think about persistent

They are still and will be needed for quite some time.  Again I'm trying to push
things a little here.  NOR flash memory is used in PDAs.  I think there is a use
for it in laptops and the use I described for servers.


>PS - I did a quick search to see if there have been any breakthroughs in
>flash other than price/density and didn't find anything.  If anybody has
>more info on this, please pass it along.

Try looking for NOR flash memory.  The price and sizes aren't where I want them
but we can still look toward the day that they will be and think about the VM
changes needed to use NOR flash memory.

Thanks, Lou

>On Fri, Jun 6, 2008 at 5:50 PM, John M McIntosh <
>johnmci at smalltalkconsulting.com> wrote:
>> On Fri, Jun 6, 2008 at 3:24 PM, Louis LaBrunda
>> <Lou at keystone-software.com> wrote:
>> > A Smalltalk program running on a server with a large amount of flash
>> memory,
>> > could run without the need for another form of database.  The flash
>> memory would
>> > be in addition to the normal memory, with both available as RAM.  The
>> flash
>> > memory would not look like a hard disk replacement.
>> You might want to do some reading about GemStone
>> http://www.gemstone.com/products/smalltalk/
>> It does much of what you discuss. They have a free version so you can
>> explore more how it behaves.
Louis LaBrunda
Keystone Software Corp.
SkypeMe callto://PhotonDemon
mailto:Lou at Keystone-Software.com http://www.Keystone-Software.com

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