Flash Based Laptops, Sooner Than You Think

klktrk,
You need to define “constant use”. Constant use of a Palm is not the same as constant use of a laptop.  Do you use your Palm for hours every day?  Do you send all of your email, do all your web browsing, all of your basic computing tasks all day on your Palm?  I’m guessing no. Your anecdotal example isn’t really a good one and here’s why.

Read cycles cost the flash memory essentially nothing (I’ve read that there actually is a read limit, but it’s so high that it would likely last years upon years).  So, as long as you’re not constantly writing new data to the flash card, it’ll go for a long time. 

So… let’s say that on a typical day, you put 5 new entries (calendar, contacts, etc) into your Palm… even if you do that every day of the year that’s still only about 1500 write cycles per year.  Assuming the worst case that you have a flash card that only lasts around 10,000 cycles, that’s still 7 years of “heavy” usage (and that’s not really a good example anyway, because you’re only performing and erase-write on a small portion of the total memory… but let’s run with it for the moment).

Now think about how a computer accesses the hard drive.  When browsing, every cached html page and image is written to the drive. On this one page alone, there are 27 items (html, images, ads, etc) Browse 5 pages of Apple Matters and you’ve got about 100 items written to the cache (let’s estimate that about 50 of the items only need to be loaded the first time and are read from the cache after that). Now multiply that by the number of sites you visit during the day adjusting for the number of pages you actually browse (5 is actually too low for this example). Suddenly, you’re up to about 1000 - 2000 file writes per day just for web browsing alone.

Try this out. Clear your cache out (in something other than Safari which doesn’t allow it) and then browse for a day. Look to see how many files are in the cache folder and how much space they take up (Make sure your cache size is set artificially high so the computer doesn’t erase old files as it goes). That will give you an idea of how much of the flash ram will need erase-writes performed.

Now add all you email, including spam and other stuff you have to delete. Word docs, text, other files you write on a typical day.

Add to that the fact that flash ram must perform its erase-writes on an entire block (even if you only need to write a word or byte), and you end up with a really large number of erase-write cycles.

... and this doesn’t take virtual memory into account. Swapping pages would absolutely murder flash ram.

To make a long story short, the usage patters of memory in a Palm versus the usage of a hard drive in a laptop are very, very different… and the article proposed that something like flash ram could replace a drive in a small laptop or as someone else suggested, a tablet PC.

Again, the way an iPod, digital camera, or Palm utilizes memory is very different than the way a computer does. I don’t disagree that as flash memory becomes cheaper and smaller, Apple will take advantage of it for devices like the iPod, and we may see the end of hard drives in MP3 players sooner than later, but for generalized computing tasks, we will need a better form of non-volatile ram… which is still years off.

You can read more about other issues with flash memory at Wikipedia:
http://en.wikipedia.org/wiki/Flash_memory

Performance degrades but over time, not in an eye blink.

Unless a lost block is an important one. If you lose file pointers to your user directory, you’re screwed.  The directory tree is one of those pieces in the file system that will need to be rewritten relatively often. It only takes one small bit (pun unintended) of bad data to totally hose your machine.

I don’t know about this, guys. Flash memory is really slow compared to today’s 7200 rpm high-cache hard disk drives. And to the guy who blamed flash memory’s slowness on USB is mistaken on two counts.

For one, high-speed USB is about 480 megabits per second, not “21 or 20”, as post #11 states. Secondly, USB flash drives are not the only form of slow flash memory. Flash memory that’s built into cameras is slow. Flash memory cards are slow (even the “ultra speed” ones are slow compared to a hard disk drive). Flash memory that’s built into MP3 players whether it be the new iPod nano, the iPod Shuffle, or some non-apple flash-based player, is quite slow compared to fast hard disk drives.

By the way, this technology already exists. I found a 2.5” equivalent form factor flash-based IDE hard “disk” drive at http://www.cdw.com a few months ago which was for sale to be used as a boot disk in industrial computers which are in dusty and high-vibration envirionments and benefit from a solid-state medium. The drives were really low capacity (about 512MB tops, I think) and were rated as being really slow. Something like 8 megabytes per second. I can’t find them again or I’d post a link.

I think I remember a time when Unisys used to use a 1 GB memory drive back in the mid 80’s to enhance their speed with mainframes. Alas, once the drive was shutdown, all the data was lost. I think once the speed of the flash memory is increased, it would be a valuble product. What about the gaming issue with flash drives?

In Fall of 2000, the median entry level PC had a hard drive roughly 20GB in size, give or take.  In the Mac world, the iMacs at the time had about half that, again give or take.  Today, just in the desktop world, this same price point comes bundled with 120GB drives, sometimes more, and over time the software and media we use and consume has grown substantially as well.  For laptops there has always been this trade off that portability leaves you with less room, and in the case of the low-end iBook probably too little (I had to upgrade mine anyway).  So by the time any of this is really available wouldn’t it stand to reason that the applications we use, the OS we run, etc. just be that much larger?

In terms of the laptop, I really see very little usefulness in terms of form factor anyway seeing that a near full size keyboard is a must. Dropping another lb. for claims of being ‘lightest’, well, that’s already been done - Sony does it what seems like every 6 months.

And in regard to power consumption…  I’m scratching my head over this one by the way:  If Flash uses less power than a hard drive, how is it that the nano has poorer battery life than the iPod mini that it replaced?

diskrichards2000

that one is pretty easy, the battery has been downsized to make it smaller and still just meet a usuable battery life.

disks eat a fair amount of power all the time that they spin.  Flash eats even more while it is being written.  However a disk spins nearly constantly, the flash write cycle is short so the net power advantage is to flash.

The fact that flash memory has limited read write cycles is a common thread among buyers of used memory. The sellers often state that the sticks were not used in routers or other such devices that get frequent r/w cycles.

Anyone have any thoughts as to how these are destroyed? Are the gates themselves disintegrating? Is it too much current? Poor manufacturing? Or, is it simply use?

hmmm… smaller battery, duh… that makes sense.

Anyway, the speed of the boot cycle of a flash-based laptop would be relative to how fast the memory itself is.  I have a mini PC that boots from a CF card fairly fast, though hardly what I would call “instant on”.  I attribute some of that to the relatively painstaking process that WinXP goes through with various drivers, etc. everytime it boots, the rest I just attribute to the bandwidth limitations of the CF format.  It’s not as fast as regular old RAM obviously.  I haven’t timed it in awhile, it’s about a year old now and hasn’t seen a lot of action since I got into Macs, but it booted about 50% faster than my regular desktop PC off a SATA RAID-0.