# MacBook Air SSD aftermarket?



## zlinger (Aug 28, 2007)

I currently have a MBA 1.8/80, and have been considering to install an SSD if the prices have started to drop. Does anyone know where I can get my hands on a 64GB or 128GB aftermarket SSD?

This would be a do it myself upgrade if it is not too difficult. I could use the old drive as a time machine backup, so will need a drive enclosure also. Many thanks if anyone has an ideas on performing this upgrade.

UPDATE: I found a vendor named Super Talent that offers a new line of 1.8-inch flash drives compatible with the MacBook Air. 

Super Talent joins hot, hot 1.8-inch SSD market

The prices are $299 for 30GB, $449 for 60GB, and $679 for 120GB.


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## billwong (Jan 6, 2002)

Unfortunately the interface is parallel ATA for the MacBook Air, not SATA like these new SSDs. This is one of the concerns with the first generation of the MacBook Air. Everything is going to/or has SATA interface, but the Air uses Parallel ATA. Hopefully there will be reasonably priced options to upgrade in the future.


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## machael (Apr 27, 2008)

The SSD Power Consumption Hoax : Flash SSDs Don’t Improve Your Notebook Battery Runtime – they Reduce It - Tom's Hardware

something to consider.


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## zlinger (Aug 28, 2007)

With regards to battery runtime, I don't buy the argument that say that hard drives are better for battery performance. At the 1.8" form factor, it is a slower drive to begin with plus that fact there are moving parts. I think the site above did testing on 2.5" drives. I'm not an engineer... but one would think that newer technology results in increased efficiency.

Furthermore, with a system being more snappy overall, you can get work done quicker, thus less runtime overall. So even more battery savings. I currently keep my MBA in sleep mode while transport, and this does drain it. Start up times are too long to shutdown multiple times per day. With SSD, you have the option of a very fast startup and shutdown.

It looks like some more PATA interface drives will be coming on line at some point... a 128GB SSD would be nice to have.

"Mtron announced the completed development of its single-level cell (SLC) 1.8" SSD which provides maximum read speeds of 120MB/sec and maximum writes of 100MB/sec. Mtron says that these speeds are over six times faster than traditional 1.8" HDDs.

In addition, Mtron also has a new multi-level cell (MLC) 1.8" SSD which delivers read speeds of 110MB/sec and writes of 40MB/sec. Both drives use a PATA interface."

DailyTech - Mtron Unveils 128GB, 1.8" PATA SSD


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## EvanPitts (Mar 9, 2007)

^^^
Hard drives that are optimized to handle sleep modes will be less power hungry than large cores of memory. Plus, you seem not to factor in that a modern hard drive has certain efficiencies in motor design, with the use of rare-earth magnets and DC brushless servo control, the motors are quite efficient.

Newer technology does not always translate into greater energy efficiently - just look at the power hungry Pentium 4's, which were a dead end because the extra power consumption was coupled with less performance overall when compared to a Pentium 3 (of which the Core processor was developed from).

Overall, there is little power consumption difference if a hard drive is set up with the appropriate sleep modes. An SSD uses less power when idling, but more when reading and writing, than a hard drive. And in benchmarks, SSDs rank somewhere in the middle of various hard drives, some HDs are more efficient and others less.

The reason for the adoption in the MBA is to make the MBA more rugged, since the SSD is not prone to self destruction if dropped or shocked - though modern hard drives are not as prone to such damage as older drives.

As for performance, you will not really notice much of a difference. When it comes down to it, the SSD is a very expensive option. Plus, there is a very limited number of manufacturers of anything in the 1.8" class, and some big players recently pulled out of the market because of lack of demand. Considering that Apple is offering the 64GB SSD option as a $1000 BTO, it's a tough sell.


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## kb244 (Apr 23, 2002)

I'm curious however. Has anyone ever tested said power requirement as well as performance of say compactflash cards which are usually used in digital cameras? 

Reason I ask, is because if the MacBook Air is a Parallell interface, and if you were not planning on installing much stuff at all. What's to keeo you from purchasing a pair of 8GB CF or a pair of 16GB CF cards and sticking them into this thing?

CF Hard Drive Adapter from Addonics

(CF cards are ATA devices so the machine would see it as if it were just another 2.5" IDE harddrive.)

I know in the past similar methods have been used for small scale thin clients or linux boxes that only required a couple gigs of storage. But usually used in desktops power requirement was never really an issue ( and was definitely lower than that of a 3.5" harddrive).

But basically, comes down to this
- 20$ USD for that adapter
- 50$ per 16GB AData CompactFlash Card (theres a number of 16GB CF cards for about 50$ to 80$, while they're not as fast as say a Sandisk Extreme IV card, neither are the 32 and 64 SSD drives for the MacBook Air). 

so you'd have 32GB solid state flash storage for about 220$ as opposed to just about any of the 1.8" to 2.5" 32GB SSD for around 500$ to 700$ (or 16GB only for around 300$)

*PS: That adapter above in single-CF format works in the older 1.8" ipod harddrive slots* (Though this one is specifically designed for Ipod with the newe ZIF harddrives : 1.8 inch ZIF - CF Adapter from Addonics )


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## kb244 (Apr 23, 2002)

By the way far as aftermarket

The 64GB SSD in the Macbook Air, is a Samsung drive. (Oh and Samsung does have a 256GB SSD, but I guess you gota sell a kidney).


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## zlinger (Aug 28, 2007)

Regardless, if it is more power efficient or inefficient, the goal is to achieve faster disk reads and writes (with reads being the majority of the demands that I do). Don't care if it uses a bit more juice. If it gets a few minutes less battery, whatever, and it may average out with other efficiencies as stated above.

But there's no doubt this technology results in a much more snappy system overall. I spent time running tests as best as I could at the Apple Store with a 1.8/64 and 1.8/80 (this is the one I'm using). If I had a MBP, or MB, I would have already seriously considered an upgrade.

SSD is for faster overall, and once you see it in action, you will understand what I mean. I'm aiming to get a 64GB SLC SDD that has a 120MB/sec read, 100MB/sec write once it is available for under $1k. Otherwise, I found one for 100MB/sec read, 40MB/sec write for about $600 (same as what is currently used).


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## EvanPitts (Mar 9, 2007)

kb244 said:


> I'm curious however. Has anyone ever tested said power requirement as well as performance of say compactflash cards which are usually used in digital cameras?


It has been done, and I was reading about it last year in an article. CF cards are slow, and in the test machine, it took 17 minutes to boot OSX. Software selection was critical, since disk walloping software like Office would simply be too slow to load. The other problem is that Flash (of any sort) has a limited lifespan when it comes to read/write cycles, and will start to develop permanent errors at about the 10,000 cycle range, and in the test machine, the system started to develop failures inside a year. However, it was a champion when it came to battery life, as they only use power when reading and writing. Perhaps a system carefully put together with the frills taken away, no Spotlight, and employing as much Portable software as possible, one could make a practical, if fairly expensive system.


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## CanadaRAM (Jul 24, 2005)

Camera-style flash drives aren't just slow - they are pig-dog slow.

This type of Flash memory cannot do random writes to a memory location -- it has to copy a whole block of the card to RAM, make the change to the one bit you want to write within that block in RAM, erase the block on the card, and then write the whole block back to the card. 

This is acceptable for a camera, where you are typically writing a megabyte or 2 at a time, in one operation, and not going in and changing existing bits. It's also acceptable for primarily read-only operations, like iPods.

But it's death on performance for a random access system like a computer's data or System drive.


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## kb244 (Apr 23, 2002)

EvanPitts said:


> It has been done, and I was reading about it last year in an article. CF cards are slow, and in the test machine, it took 17 minutes to boot OSX. Software selection was critical, since disk walloping software like Office would simply be too slow to load. The other problem is that Flash (of any sort) has a limited lifespan when it comes to read/write cycles, and will start to develop permanent errors at about the 10,000 cycle range, and in the test machine, the system started to develop failures inside a year. However, it was a champion when it came to battery life, as they only use power when reading and writing. Perhaps a system carefully put together with the frills taken away, no Spotlight, and employing as much Portable software as possible, one could make a practical, if fairly expensive system.


Can either you or CanadaRam produce some links to where these tests were done and on exactly which brand of Cards and models? 

I know that some of the highest end cards (Say Sandisk Extreme IV, which are designed to put up with a crapload more abuse than say your typical SimpleTech, PNY or etc consumer cards) usually get bout 45MB/sec, I'm assuming that maybe the big SSD drives do better. Also is 45MB/sec faster than a magnetic harddrive ( not talking what the bus theoreticaly could do but what the actual harddrive can do).

Booting off an external harddrive with OS X only takes about 2 mins at most ( a little slower than my internal SATA). USB 2.0 throughput is 480mbit (Bout 60MB/sec in optimal conditions, so its likely to be slower), the CF cards are about that if not better in some cases especially if plugged internally. So the 17 minute boot time makes me extremely skeptical of the source you quoted.

Now if we're talking bout the cheapest card posisble such as SimpleTech (pratically a rebranded 'regular' sandisk card), or some chinese made one, then we're looking at less than 3MB/sec then those results would certainly be true, and they don't put up with much abuse either. (tho they still have a much higher shock resistance than magnetic media)

*Edit* One of the 32GB SSD drives on the market at bout 500$ quotes roughly 100MB/sec. It's an SATA SSD tho.


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## kb244 (Apr 23, 2002)

CanadaRAM said:


> This is acceptable for a camera, where you are typically writing a megabyte or 2 at a time, in one operation, and not going in and changing existing bits. It's also acceptable for primarily read-only operations, like iPods.


Try 8MB to 12MB at a time. My raw files on my Pentax K10D DSLR is typically around 6 to 8 megabytes, and I don't have to wait to take the next shot. Last time I seen *most* cameras take something only 1 to 2 megabytes was probably 4 to 5 years ago.

(My friend's Nikon D300 makes 25MB files, and it writes those at once and finishes before the third shot is taken).


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## zlinger (Aug 28, 2007)

Price just slashed on MacBook Air for SSD by $500. I hope the prices are beginning to fall now.

AppleInsider | Apple lops $500 off the price of SSD-based MacBook Air


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## kb244 (Apr 23, 2002)

zlinger said:


> Price just slashed on MacBook Air for SSD by $500. I hope the prices are beginning to fall now.
> 
> AppleInsider | Apple lops $500 off the price of SSD-based MacBook Air


Basically probably cuz people were probably catching on that the SATA version of the same Samsung 64GB SSD drive ( which is faster 80 to 100MB/sec as opposed to 35 to 66MB/sec) was only 799$ compared to the extra price Apple wanted for the Parrallel ATA version at a slower speed.  (Doesn't surprise me, Apple had always had an ridiculously excessive charge for Ram and HDD upgrades).


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## CanadaRAM (Jul 24, 2005)

kb244 said:


> Try 8MB to 12MB at a time.


The point is that the fact that camera flash RAM can only do block writes is A-OK if all you do is block writes (1GB - 12 GB it's immaterial) 

But REGARDLESS of the 'rated' speed (and you will not get a sustained 45 MB/s out of a flash card) the problem is that they cannot do single bit changes or writes. So for any random access writes, it has to copy, change, erase and rewrite 8K or more -- so if you're only changing a few bytes. and doing that repeatedly (typical behaviour - for a computer) you have to stop and wait while it goes through that routine every time. So -- like the Ferrari that can do 165, it's all about the stop lights downtown, not about the maximum flat-out speed.


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## kb244 (Apr 23, 2002)

CanadaRAM said:


> The point is that the fact that camera flash RAM can only do block writes is A-OK if all you do is block writes (1GB - 12 GB it's immaterial)
> 
> *But REGARDLESS of the 'rated' speed (and you will not get a sustained 45 MB/s out of a flash card) the problem is that they cannot do single bit changes or writes. So for any random access writes, it has to copy, change, erase and rewrite 8K or more -- so if you're only changing a few bytes.* and doing that repeatedly (typical behaviour - for a computer) you have to stop and wait while it goes through that routine every time. So -- like the Ferrari that can do 165, it's all about the stop lights downtown, not about the maximum flat-out speed.


CF flash can do single bits, But based on your logic nor can SSD do that, because the 8K and such is based on the file system formating, how the clusters and sectors are formated and such. You could do a single bit modification if you specifically told it too but most file operations don't. CF cards are ATA devices just like standard harddrives so the commands it accepts should be the same. So I'm not sure where you are getting your information. And the Extreme IV and Ducati Line can have sustained write speed of 45MB/sec (just inside of a camera thats never gona happen).

Thus far the only real difference I've seen between quality CF card versus SSD devices is that the SSD devices can be twice as fast (SATA-II), but requires more power, and you can get an SSD device in larger capacity than 16GB. Their memory addressing, and file allocation wouldn't be any different from each other.


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## EvanPitts (Mar 9, 2007)

kb244 said:


> Can either you or CanadaRam produce some links to where these tests were done and on exactly which brand of Cards and models?


I had come across the article on LowEndMac, I think, but it may have been one of the other tech sites. Googleing should yield the appropriate article, and perhaps newer tests that have occurred since.



> I know that some of the highest end cards (Say Sandisk Extreme IV, which are designed to put up with a crapload more abuse than say your typical SimpleTech, PNY or etc consumer cards) usually get bout 45MB/sec, I'm assuming that maybe the big SSD drives do better. Also is 45MB/sec faster than a magnetic harddrive


The difference if that the baseline methods of storage are different. People get fixated on "speed", but in essence, the real throughput of a drive stems from a number of factors. An expensive CF device will feature extra protection, even to the point that if you spend enough cash, you can get a radiation hardened one for a cool half million dollars for a deep space probe. However, the memory can not be infinitely cycled as in a hard drive, and a CF drive will develop . An OS like OSX will simply murder the device with the number of times it has to hit the virtual memory - which is a very real limit. Plus, even the fastest drives only accomplish that speed by segmenting and interleaving the storage (though hard drives also use this strategem though the user will never know).

CF is much different from a true SSD, as a CF device will degrade over time, while an SSD will keep on running. In a camera, CF is entirely fast enough, and is lower cost when compared to SSD, and more robust than a hard drive.

As for practical use speed, a CF device will yield much slower response time, especially when the OS is hitting the VM. They are not very good within multiple task environments, as the pure speed of reading and writing is overhauled by the latency of changing addresses and recirculating the data.

But people have tried it, mostly to extend battery times, though there is little practical benefit because you can buy an awful amount of hard drive for a paltry amount of CF/SSD...

[/QUOTE]USB 2.0 throughput is 480mbit (Bout 60MB/sec in optimal conditions[/QUOTE]

Doubtful, since 480Mb/s translates to 48MB/s - then you have to lob off the handshaking times, channel reversals, etc. and you are left with not much more than 20MB/s in practice, if you are lucky).



> So the 17 minute boot time makes me extremely skeptical of the source you quoted.


We are not talking about USB style devices that are run in one direction only. When you put a CF card into a card reader and download, data is moving in one direction only. In a CF card, there is a very real latency time between reads and writes, and the OS does read and write simultaneously when booting - plus dipping into the VM when needed. So using a CF card as a hot bootable system is sluggish - as it is completely different from a true SSD drive in topology and technology. Plus, there are some "CF" cards that are not flash based, but in fact, have a hard drive in them, and they tend to be quite quick. They are used to provide lots of portable storage in the CF footprint, which would yield no benefit over just running a hard drive.

If I wanted more response out of a system - I would opt to use more optimal software, as well as leaning out the OS and turning off extraneous features - as that will yield much more performance than wedging something like Office onto an expensive and exotic SSD. And one could always opt for a faster hard drive solution, which is more conventional.

But if this is for an MBA, then really, you do not have much to start with because the response time is more hampered by an underpowered and overheated Intel processor coupled with a crummy fake video card - rather than the small difference between a hard drive and solid state drive in real usage.


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## kb244 (Apr 23, 2002)

EvanPitts said:


> *We are not talking about USB style devices that are run in one direction only.* When you put a CF card *into a card reader and download, data is moving in one direction only.* In a CF card, there is a very real latency time between reads and writes, and the OS does read and write simultaneously when booting - plus dipping into the VM when needed. So using a CF card as a hot bootable system is sluggish - as it is completely different from a true SSD drive in topology and technology. Plus, there are some "CF" cards that are not flash based, but in fact, have a hard drive in them, and they tend to be quite quick. They are used to provide lots of portable storage in the CF footprint, which would yield no benefit over just running a hard drive.


You just contradicted yourself.

Let's reiterate
1) I was NOT talking bout using a CF card in a USB reader, but rather directly attached to the computers IDE port. 
2) I clarified that a external USB harddrive enclosure, which you just confirmed was asychronous, could boot up OS X in under 2 minutes, Your previous statement said 17 minutes for a CF card, despite that an external HDD enclosure which would run at lower speeds than a directly attached CF card was booted in less time than you stated. 

And yes I know about the mini harddrives, they're called Microdrives, and nortoriously easy to damage. Microdrives are actually very slow compared to compactflash cards with actual solid state memory in them. Their only real benefit now days is that they are extremely cheap (12$ for a 6GB microdrive).


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## kb244 (Apr 23, 2002)

EvanPitts said:


> CF is much different from a true SSD, as a CF device will degrade over time, while an SSD will keep on running. In a camera, CF is entirely fast enough, and is lower cost when compared to SSD, and more robust than a hard drive.



CF and SSD are not 'much different'. both Compact Flash and SSD are Solid State storage devices. SSD will degrade over time as well, maybe not as quick as a cheaper product.

Lets also keep in mind that thin clients, and Novel clients and so forth have been running compactflash cards in them for over 8 years without a problem.


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## kb244 (Apr 23, 2002)

EvanPitts said:


> Doubtful, since 480Mb/s translates to 48MB/s - then you have to lob off the handshaking times, channel reversals, etc. and you are left with not much more than 20MB/s in practice, if you are lucky).


There are 8 bits in a byte , 480 MBit = 60MB/sec, But you just again confirmed my point about how I was able to boot off a USB external harddrive in less than 2 minutes, ergo if a CF card is faster directly connected to the IDE channel, then wouldn't the USB external drive be much slower than 17 minutes?


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## kb244 (Apr 23, 2002)

Back in 2007 (note the prices droped a crapload since then)

Compact Flash Faster than a Hard Drive, CF in a Clamshell iBook, eSATA for PowerBooks, and More


> Following up on Compact Flash Hard Drive Options, Jeffrey Bergier says:
> 
> I have a success story for you.
> 
> ...


and



> Jeff,
> 
> Wow, that Lexar is fast - it's rated at 300x! (1x = 0.15 MB/sec., the original CD-ROM speed, so 300x is 75 MB/sec. That's in the same range as a hard drive and faster than USB 2.0 or FireWire 400.)
> 
> ...


I'm still trying to find an article on lowendmac where it actually says the cards are painfully slow, and haven't made their system any faster.


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## EvanPitts (Mar 9, 2007)

kb244 said:


> CF flash can do single bits...


To the outside world, it looks like it, but internally, each segment of storage has to be rotated over it's whole length, whatever length that may be, whether writing one bit or the whole segment. CF is not "random access", but the intelligent controller that runs it makes it look that way. The setup of the memory cells is dependent upon the construction of the core of the device, and it independent of the drive geometry it emulates. This is the same with all Flash type devices.



> Thus far the only real difference I've seen between quality CF card versus SSD devices is that the SSD devices can be twice as fast.


CF is Flash based, while SSD is more like a huge random access memory bank, and that is why SSD is fast, because it is capable of real random access while CF and similar devices only emulate it. It doesn't make CF bad or anything, it is just a different storage medium with different properties that are used for different purposes.


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## kb244 (Apr 23, 2002)

EvanPitts said:


> CF is Flash based, while SSD is more like a huge random access memory bank, and that is why SSD is fast, because it is capable of real random access while CF and similar devices only emulate it. It doesn't make CF bad or anything, it is just a different storage medium with different properties that are used for different purposes.


I found what you were talking bout, and guess what even SSD are Flash-Based, some are DRAM based (but the latter if power dies so does all your data). 



> An SSD is commonly composed of either NAND flash non-volatile memory or DRAM volatile memory.
> 
> *Most SSD manufacturers use non-volatile flash memory to create more rugged and compact alternatives for the consumer market. These flash memory-based SSDs, also known as flash drives, do not require batteries, allowing makers to replicate standard disk drive form factors (1.8-inch, 2.5-inch, and 3.5-inch).* In addition, non-volatility allows flash SSDs to retain memory even during sudden power outages, ensuring data retrievability. *Though flash SSDs are significantly slower than DRAM, they still perform better than traditional hard drives, at least with regard to reads.* Flash SSDs have no moving parts, thus eliminating spin-up time altogether, and greatly reducing seek time, latency and other delays inherent in conventional electro-mechanical disks.
> 
> ...



So basically DRAM based SSD drives are actually RAM that requires power to retain data, but has a backup mechanism in case the power is killed. So its basically like a big ass ram drive with backup storage (so a 64GB drive is actually 128GB).

But basically put neither of us were totally wrong or totally right, CompactFlash cards are Solid State Devices, they're just flash-based, and SSD drives are commonly Flash-Based unless you pay the extra Money for it. (tho even DRAM is flash based, cuz it uses flash for the backup).


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## CanadaRAM (Jul 24, 2005)

kb244 said:


> an external HDD enclosure which would run at lower speeds than a directly attached CF card


Your basic assumptions about CF cards are flawed, which shoots your whole argument. You are assuming that the advertised specs are actually related to real world performance, and that that performance will be maintained in all modes of operation.

A CF card can only write sequentially, and only to an empty block. If there is already something in the block it has to be copied to RAM, manipulated, erased and rewritten. This is completely different from a hard drive (and it is enormously time consuming, relative to hard drive latency)

The high 'rated' speed of flash cards is a theoretical maximum speed, not real world -- it is marketing numbers, just like the $199 home theatre system with '1,000W Peak music power'. 

The ONLY time you get anywhere near the rated speed of a flash card is when you are writing files sequentially to an erased card. Stop a moment to wonder why cards are advertised at "266x speed" and "300X speed" and 45 MBs... and then a new type of cards (SDHC) had to be brought out, which can be guaranteed to maintain a minimum write speed of 
* Class 2: 2 MB/s
* Class 4: 4 MB/s
* Class 6: 6 MB/s <-- note the *real *speed of the high end card here... 

..because the 'high speed 45 MBs' cards couldn't hack it when put to the test by high resolution cameras and flash based video cameras.

Wiki

Like we have said before -- Conventional Flash works fine for cameras because the mode of use suits the limitation of the media. Works like poo for typical hard drive use.

Digg - Addonics CompactFlash Adapters Replace Notebook Hard Drives


> To put it in perspective for you, On an AMD Sempron 3000 with 1GB RAM I put a small Linux distribution on a 1GB CF card, I used a CF to IDE converter. It worked but it was painfully slow! For 20 minutes after booting I saw the letter " L " then I saw an " I " and I realized it was LILO which should have taken seconds too what seemed like forever. I gave up before the next L appeared.


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## kb244 (Apr 23, 2002)

I wonder if that means, in the event that the Macbook Air actually somehow surges the SSD then everything on the SSD since the last bootup gets killed?


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## EvanPitts (Mar 9, 2007)

kb244 said:


> I wonder if that means, in the event that the Macbook Air actually somehow surges the SSD then everything on the SSD since the last bootup gets killed?


No, since SSD is different from Flash based systems like CF and SDHC. Well, if it was some kind of power surge, the drive could be killed, but so would a hard drive.

The main killer is the fact that entire segments of the storage have to be circulated around. This is the same kind of concept that was behind Bubble Memory storage systems that were the rage for a while. The speed of the memory was hampered by the fact that the memory had to be circulated (and in Bubble Memory, it was actual physical circulation) - so it ended up that Bubble Memory in practical use was slower and less reliable than a good old clunking Shugart.

Now, there is provision for "fast booting" Leopard, if I recall correctly. I think the system makes an image on the drive, then shuts off the main memory. When the system is awakened, the image is quickly restored to the main memory, so it looks like the system is booting fast, but rather, it is just running from where it ended. But I could be wrong because it was a while ago when I was reading about such things.

I do not know if one would get much of a real world performance boost by going from a hard drive to a solid state drive, though one would obviously make a gain in physical reliability, especially in view of the price versus storage factors. Not that there is anything wrong with SSD, but the price premium may not be worth it.

CF would make for a slowish system, though if you really wanted a laptop that was champion at battery life, then a Pismo with CF and two batteries would probably be the system of choice - well, outside of an OLPC XO which is really low powered...


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## kb244 (Apr 23, 2002)

EvanPitts said:


> No, since SSD is different from Flash based systems like CF and SDHC. Well, if it was some kind of power surge, the drive could be killed, but so would a hard drive.


Did you just ignore everything I said? I Already said what SSD was, If its wasn't flash based (which trust me, some SSD are indeed flash based), then it was DRAM and DRAM contains volitile memory (like RAMS in your computer), plus flash based memory. Because it contains a battery if the power shuts off it moves the volitile memory into the flash memory for safe keeping, but loads it back up into volitile memory on start so that it gets it's peak performance.

But a harddrive would least still have sectors and such untouched that could probably access (albeit expensive depending on the damage), where as volitile memory is just... gone. Like if you shut off your computer and you didn't save something on textedit.


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## kb244 (Apr 23, 2002)

EvanPitts said:


> The main killer is the fact that entire segments of the storage have to be circulated around. This is the same kind of concept that was behind Bubble Memory storage systems that were the rage for a while. The speed of the memory was hampered by the fact that the memory had to be circulated (and in Bubble Memory, it was actual physical circulation) - so it ended up that Bubble Memory in practical use was slower and less reliable than a good old clunking Shugart.


It sounds like what you're refering to is how CCD sensors work (Charged Coupler Devices). A pixel in the middle of the sensor couldn't just be simply read, it had to read thru all the pixels before hand to get there. (though CCD oddly enough are faster at capturing at once since the whole rows get charged thru rather than on a per pixel basis, but the idea of following the chain is bout the same).


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