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Flash Drives in Future Apple Laptops?
danscript writes "Samsung hopes that falling prices for flash-memory chips will mean solid-state memory can eventually replace hard-disk drives in Apple PowerBooks and iBooks as well as other devices, Macworld UK is reporting. The benefits? - silent; less power; reliable and faster."
They must be talking about some other kind of flash than anything I've used... I routinely rewrite 128MB-512MB CF cards for an embedded product and it's nowhere near the speed of a laptop disk. Maybe they're thinking some sort of RAM cache.
The point he's making is that the controller on harddrive have a relatively fix amount of transistor, regardless of the harddrive's space. Flash mem, however, needs a set of transistor for every bit of data it stores.
In US, you can easily buy enough major firearms to wipe out your neighbourhood but a few little fireworks are banned.
The drives are also typically lighter and can read and write data faster than conventional drives.
AFAIK, flash memory reads data faster than a hard drive, but writing is slow as hell because of the long block erase cycles,
does samsung have a new technology for flash chips? :-D
or do they eventually use MRAMs?
> These conditions include higher levels of oxygen,
> and the like commonly found on airplanes
Huh?
On your average pressurized commercial aircraft, the ratio of oxygen to nitrogen should be unchanged (just available to your lungs at a lower pressure). In fact, the only place you're likely to find *more* oxygen is on an unpressurized aircraft that requires you to wear an oxygen mask at higher altitudes. In which case, even "mustache wax" can be a fire starter.
And under certain other conditions, people have been known to burst in to flames. Oh wait, no they haven't. Come on, seriously, do you have ANY idea how many flash drives are currently brought on Airplanes? I've brought my digital camera, MP3 Player, and thumbdrive, all which have flash memory/drives. No fires.
On the other hand, you might be thinking of bubble memory... which was going to be the next big thing in the early 80's. Still waiting on that one.
Am I part of the core demographic for Swedish Fish?
http://www.physorg.com/news4220.html
Sdelat' Ameriku velikoy Snova!
Flash chips have a interface similar to RAM chips (address / data bits, chip select, write enable, ...) If your filesystem is corrupt, you can still read the data contents byte-wise,
http://news.designtechnica.com/article7516.html
It might help to read the original article. Note, for example, that the drive uses the "industry's highest density 8 GB" flash to create 16 GB drives, meaning the drive probably uses striping. Also, the drive's performance seems to be pretty good:
"The SSD's performance rate exceeds that of a comparably sized HDD by more than 150 percent. The storage disk reads data at 57 MegaBytes per second (MBps) and writes it at 32MBps."
Conservatively, that's right on par with the fastest non-SCSI drive in the world, and by the time it's released, it will probably be able to directly compete with 10,000 RPM SCSI drives. When you consider that this drive weighs half of what a regular hard drive does, uses 5% of the power, gives off minimal heat, and won't break if you don't treat it perfectly (I've had to bring my iBook into the shop twice, both because the hard drive broke), is there anything to complain about?
That's true if each block of the disk was written equally often. AFAIK, unless you use special file systems, that's not the case with common file systems today. Let's say you write one file once and only read it from then on. The access time would get updated each time, wearing out a single block faster than the rest.
Of course it runs NetBSD. BTC: 1NT7QvbetmANwaMzhpVL6
Maybe because that is going through your USB port...
The ipod mini uses a hard drive. 4gb in the 1st generation and 6gb in the 2nd. The iPod shuffle uses flash.
Gone!
http://www.m-systems.com/content/Products/product. asp?pid=34
M-Systems has been providing fast FLASH based 2.5" laptop drives in the 1 GB to 128 GB range for a while - while they are god awful expensive, they do work very well and I have used them in several mission critical applications. My hope is that Samsung can get the price point down by an order of magnitude (or two)
here you go:
. asp?pid=34
>5,000,000 Write/Erase cycles, unlimited Read
http://www.m-systems.com/content/Products/product
I googled. No such thing. Sorry.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
I'm guessing these drives would have a sort of "wear leveling" just like they have in most compact flash cards.
The wear leveling works by keeping a table of what physical flash is mapped to what address. The trouble comes when power is yanked whilst the table is in the middle of an update.
Brett
I've even read articles
/. then?
What are you doing on
but seriously, prior to wear leveling (ie: antique 32MB cards, early controllers/drivers etc..) this was a valid statement, however cards back then only had 10k or fewer rewrite cycles. the rewrite cycles have gone up 10 fold, and wear leveling makes sure that data that is 'rewritten' is actually written on a portion of the disc that was previously determined to be a low write, freely alloctabale block, and they always keep spare low write sectors available. it's even possible for a hard drive such as this to Warn users of impending drive failure. BTW when a block on a 'flash' based drive 'fails' it falls back into read only mode. only the data it attempted to write must now be written somewhere else.
Also, to get back on track the MTBF for most platter based hard drives is something along the lines of 50,0000 hours for a really top notch drive, reading/writing the entire disc will on average take ~2 hours, requardless of capacity, because that's how long it takes the data heads to travel the entire platter surface area... so statistically, you have 25k write cycles before failure on a conventional hard drive. so how is that inferior to flash memory? and remember, this is APPLE Macintosh running of a FreeBSD derived kernel. put the right amount of ram in the laptop, and it will _never_ use swap space.
https://www.gnu.org/philosophy/free-sw.html
Hard cards were the original IDE drives. Before hard cards you had to have an actual disk controller plugged into your bus, then cabled to the drive. IDE, in it's original implementation, was just an ISA slot re-configured as a pin header connector with some unneeded pins (such as all the IRQs except for 14 or 15) removed.
With all the advances that IDE has taken, it is still a simple interface, not a disk controller.
Hard cards didn't last long, but they're an important mutation in the evolution of the modern PC.
-Peter
Serial is by far not even close to dead.
I deal with so much equipment that has a life cycle in the 30+ years that it's just amazing by comparison. So in another 10 years when more long lived technology has died off we might see the end of serial, but there is simply too much non-pc equipment in the world to do away with it.
Nearly every electronic requires a serial port or some form there of.
It's slow, clunky and definatelynot the newest thing, but it's a good standard and far too many things in this world require it.
Now, think about the devices in your home and ask yourself how many can do serial communications. (Hell even my cable box does)
"You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
In fact, here's a white paper from Sandisk.
Brett
Gigabyte is preparing an interesting solution. AnandTech give us a brief overview as seen in the last Computex:i =2431&p=5
:)
http://www.anandtech.com/tradeshows/showdoc.aspx?
Basically they just use ordinary DDR and use a pack of batteries to keep the data when the computer is powered down. The batteries have a maximum life of 16 hours. So this is for enthusiasm that leave their computer always on. I wouldn't install an OS on this since in case of long power failre you would loose eveything, but I really wish I could have one so that I could install Battlefield 2 on this. It certainly would lower the very long load time.
It used to be higher, (up to 100,000), but new MLC flash has lower numbers. Note that the 1,000,000 numbers you read is low-density NOR flash, not the NAND flash a hard drive would be made of.
You must wear level, so the real life of the drive is basically 10,000*num sectors writes. A sector is 128KB or so, depending on the flash type.
This seems like a lot until you realize that often you write sectors over and over. Also, due to the large sector/page size of flash, you end up doing multiple writes when you think you are doing a single one. For example, if you write to a file in 4 chunks, 32K at a time, it uses up 4 of your writes. It might be possible to remove this with intelligent caching, but you're gonna need a lot of RAM for the caching.
Honestly, this is just an idea that isn't ready yet. Flash is too slow to write right now. The life is decent. Reads work well.
Not true. Modern Flash cards have wear leveling built into the hardware. The address the computer sees is actually the logical address that the controller translates to a hardware-specific address. The controller automatically adjusts addresses to spread out the writes and to detect and remap bad blocks (this should occur without loss of data, since blocks only go bad when you write to them).
Back when Plus Hard Card was new thing there were no such thing as IRQ 14 or 15 on typical PC. IBM PC was still running on 4,77MHz and using 8-bit slots with IRQ's 2-7. It was not even possible to install it to 16-bit slot of IBM AT because 16-bit part of ISA slot was blocked by frame of card. Of course most AT systems had also 8-bit slots for this particular reason so installation was still possible.
They didn't use IDE-like drives either. Controller part of board was fairly complex with multiple large chips.
There were lot of clones that were'nt as plug-and-play as original Plus Hard Card was. Clones were just 8-bit MFM/RLL (and later 16-bit MFM/RLL/IDE/ESDI/SCSI) controllers mounted to metal plate with normal 3,5" HDD.
Quantum bought Hard Card manufacturer eventually as someone already wrote.
Hard Cards from various manufacturers lasted quite long. I'd say around 10 years eg. from 1985 to mid 90's. I considered 10 years pretty long time in computer industry.
There's link to photo of original card. Text talks about smallest being 20 MB, but first model was actually 10 MB.
http://incolor.inebraska.com/bill_r/hardcard.htm
Which USB stick do you have? The Lexar JumpDrive Lightning reads at 22 MB/s. ArsTechnica review.
i know for digital cameras there is enough difference with some brands of flash memory that it will effect how long you wait between shots (at least for cameras without internal memory to buffer it). if you figure the transfer of one JPEG is that noticeable, then transferring real data would matter too.
i guess if you have the buffer of internal memory in your camera, you will not notice. so the cheaper, slower flash cards are effectively the same.
They're out there in the embedded market, where your option is paying more for a flash disk or having your spinning mag plates fly apart because of shock/vibe.
. asp
. asp?pid=41
http://www.m-systems.com/Content/Markets/Embedded
As others may have noted, there are different kinds of flash, some that have good write performance, some that have good read performance, and some that have both.
And if you want to pay, you can get an Ultra320 flash disk:
http://www.m-systems.com/Content/Products/product
Outside of a dog, a book is a man's best friend. Inside a dog, its too dark to read.
This has to be the best troll ever.
I googled for "Flash omium potential" and no hits. Google being google, I'm sure your post and this discussion will be in the index soon, so no worries - soon googling for "Flash omium potential fire hazard" will turn up enough hits for people to believe its a real problem.
Even better you said
"These conditions include higher levels of oxygen, and the like commonly found on airplanes."
Firstly, flash memory, like all IC's is sealed. Levels of oxygen around it can't affect it. Secondly, airplanes don't have "higher levels of oxygen" as far as I know. Thirdly, I work with flash memory a lot, and I've never heard of this scare story.
And then the killer
"Does this mean that the use of iBooks and PowerBooks will be banned on airplanes?"
There's no reason for them to be, but you're working hard on it. I must say, I like idea of me taking out my cheap plastic Fujitsu laptop, and yuppie next to me taking out his ultra hip (and ultra expensive) Powerbook only to be told he can't use it because of some bullshit firehazard while I work away.
Powerbooks are a firehazard BTW - their cases are made out of a material which is fire hazard. Even worse, terrorists may ignite them with a blow torch deliberately. The Department of Homeland Security must protect the homeland and band them now.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
http://en.wikipedia.org/wiki/Spontaneous_human_com bustion
Actually, you might be right.
I've got 1 GB of RAM on my Fedora Core machine and even though I use GNOME heavily and even use the machine to compile source (even kernel source) and I gotta say that the machine hardly ever has to go to swap. Right now I've got OOo, Firefox and a couple of terminal windows going and even opening files and such in OOo, this is my vmstat output
[me@host ~]$ vmstat 5 5
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
1 0 5320 4996 364188 220788 0 0 8 11 45 15 16 20 64 0
0 0 5320 5012 364188 220788 0 0 0 8 1061 776 14 2 84 0
4 1 5320 4420 364364 221124 7 0 106 2 1178 1596 29 5 59 7
0 0 5320 3016 364568 222264 0 0 222 67 1228 1148 21 5 66 7
0 0 5320 3032 364568 222264 0 0 0 3 1139 1090 19 3 79 0
As you can see, very little swap activity; only 7 pages were swapped out and this machine has been up for 10 days.
My blog
The flash is broken up into Erase Units, which as the name suggests is the smallest block you can erase at any one time. IDE hard disks have a small fixed sectorsize of 512 bytes, smaller than one EU.
Imagine a 12KB flash with a 2KB Erase Unit and 6 units. One of these is bad - this can seen by the absence of a metadata signature for example.
You could use this as an IDE disk with 6KB capacity, since some of the erase units needs to be spare at all times.
Each EU can hold 3 IDE sectors, some metadata including the signature, and then 3 integers saying which logical block the physical block holds.
The EU starts off erased, all ones. Let's write a fileystem,Now imagine we need to update sector 1. We can use one of the spare blocks to store the data. The old copy can be left, but marked as unused by setting its lookup table entry to 0 - programming all the remaining bits.Now imagine that you need to write the next two blocks, 2 and 3. That way all the blocks in the first EU will be obsolete, and you can erase it.If you're not lucky enough to get all the blocks written at any one time, you need to compact by copying the block with the most obsolete blocks into one of the spare EU's. Obvously you can skip the obsolete blocks - you just copy the ones that are used and mark the rest as spare.
So far I've talked about one lookup table, the one in the flash which gives you the logical block which each physical block contains. This is the inverse of the lookup table you want for reading an arbitrary block, but this inverseness gives it the useful property that it only needs to be updated only once per erase cycle - some of the bits in an entry are programmed when the block is written, and the rest are programmed when the data becomes obsolete.
If you want to read logical block N, it's useful to have another lookup table which gives you the mapping logical block to physical block. This will need to be updated a lot - once for each write of a block. But it can be generated from the lookup table in the flash at insertion time, and kept in Ram.
There are some corner cases obviously - like the bad bits in the metadata area or whole EU's going bad, but there's usually a fair bit of space in an EU for metadata, and a reasonable number of spare EUs. Plus, if the flash has always been used like this, the bits should all wear out at the same time, which is obviously not something you can work around. But the trick to avoiding the problem you mention is to store an _inverted_ lookup table on the flash.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
theres also yaffs which requires less memory and runs faster on NAND flash chips, which is the type of memory that would be used for that kind of storage. NOR is slower has larger pages, it's usually used as ROM chip.