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Disk Drives Explained
CowboyRobot writes "Magnetic disk drives are one of those things I usually take for granted without thinking about, but I recently realized how little I understood about how they really work. ACM Queue has an article from their 'Storage' issue titled, 'You Don't Know Jack About Disks', which does a very good job of explaining exactly how magnetic disks have evolved since the 70s and how they work today."
Fucking bullshit.
heh, always wanted to do that
more /usr/src/linux/drivers/block/floppy.c
It's all in there.
an in-depth explanation of a medium that should have been phased out five years ago. Now if they'd only explain the Nintendo GameGlove to us...
Windows XP SP2 told me to install third-party software that prevents viruses and protects stability... I chose Ubuntu
I have been already sick of people with whom I tried to talk about computers only to discover after two hours of conversation that they in fact have no idea what SCSI means for gods' sake, let alone ZBR. I do really hope there will be more introductory papers for beginners like this one, to which I could point people before another time I answer their question: "What computer should I buy?" I think Dave Anderson once again has done a great job. Thanks!
Karma: Positive (probably because of superiour intellect)
Could somebody mod bomb that fucktard?
It's not too hard for ordinary people to understand (I can understand it and I'm not an expert in hardware), though the article didn't really talk about USB thumb drives, etc.
What kind of controller interface do they (thumb drives) use? ATA, SCSI or something else?
Wow, another article explaining something most of us should already know about. Wooooo Hoooo! A more useful article would be about Magnetic TransWarp Toilets. If you've ever used one, you know why they're so exciting to see and use. The chewing sounds you hear after it sucks out the poo and pee is so amusing. I like to hear it fart.
woot!
It always intresting to see how things work. Nice little thing to add to this is the way Nintendo do copy protection on their disks (although not scritly on topic). Instead of relying on heavy software encryption they went for a nice simple solution. They spin the CD-Rom the wrong way. As such you need special burners if you want to copy it.
Now thats a neat idea
Rus
Cheap UK and US VPS
Thanks, a learned a lot. I really like slashdot and all the great articles and friendly people that talk here. I'm going to tell all my friends about it too.
No way d00dz. Now I'm gonna haffta tell the kid at my school who built a Hard drive for his science fair project to read that article. I feel so 1224.
-- "Why would you quote your self?" -Me.
"Fatal error: Call to undefined function: message_die() in db/db.php on line 88"
So... anybody got a mirror?
fsck -u
To take the IBM mainframe example he quotes: yes, IBM originally used a CKD (count-key-data) architecture and this was still preferred in the late 1970s for highest performance applications. However, in the last 1970s, IBM already provided FBA (fixed block architecture) disk drives such as the 3370. These moved intelligence of disk geometry into the disk controller and were quite easy to program.
Other mainframe and minicomputer manufacturers had innovative schemes during the early 1980s.
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Mea navis aericumbens anguillis abundat
what about those crazy MFM drives from the old IBM XT's (if you were lucky enought to have a HD back then, I had 10 MBs! )
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Brackets contain world's first nanosig, highly magnified:[.]
looks like their disk drive got slashdotted
Furthermore the rare element production takes often place in very anarchic countries like Kongo or Liberia. Usually warlords and local terrorists use the money from the disk drives rare elements to finance their blood raids and terrorship.
That's btw the reason why the US were setting up Kabila in Kongo. This guy was killed, but only because the French were more clever.
So, instead of this old technology which is going to be phased out in 5 years anyway, you should use more modern flash/ram disks and DVDs for data storage, just for moralic reasons.
Think about it: If you refuse to buy bananas or big name brands because of the cruel, inhumane exploitation of the third-world workers, then you should do the same in IT and avoid disk drives.
Owner of a Mensa membership card.
There are probably lots of articles on the subject that can be bought up with a quick search, but my favourite broad explanation site has their definition here.
Well, there's an interesting article about hard drives here. Watch out, though, it's quite long and it's an easy way to waste some hours... But sure you wanted to know why we don't need to park the hard disk's heads anymore? =) Or, that in fact, there are holes in the hard drive, so it can "breathe".
On page 6 (ATA versus SCSI) Mr. Anderson (insert matrix joke here) references "ATA versus SCSI: More Than an Interface," by Dave Anderson, Erik Riedel, and Jim Dykes.
The pdf can he had here: ATA_vs_SCSI
I thought it was quite an interesting read, and an excellent companion piece to the "You Don't Know Jack about Disks" article.
RFC2119
Unfortunately, we're still quite a ways from developing solid-state drives cheaply that can finally compete against today's hard drives.
:-)
I think within the next 15 years we will finally see the breakthrough that will essentially turn our primary storage into physically-removeable cartridges of solid-state non-volatile memory storing over 250 GB of data on a cartridge somewhat smaller than the physical dimensions of a 3.5" floppy drive. And unlike today's non-volatile memory, the new solid-state memory can be erased many trillions of times without affecting the life of the memory.
The big advantage of solid-state storage is that since the delay in reading and writing data is a tiny fraction of that of hard drives, they could access data at extraordinarily fast speeds. Imagine loading something like Windows 2000 Professional in under two seconds from start to finish!
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;)
--
This type of explaination is ILLEGAL. If you explain Disk Drive YOU MUST PURCHASE SAID DRIVE. We are going to see that this website is taken down immediately. We will log IP addresses of anyone who visits this site and we WILL find you and prosecute you to the maximum extent permissible under the LAW.
Else you'd also wind up supporting the use of magnetic hard drives....
"To confine our attention to terrestrial matters would be to limit the human spirit." -Stephen Hawking
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Yup, my hard drive did that a few weeks ago...
Chuck Norris: Socialism == a thousand years of darkness.
That server's gotten /'d, so here's a mirror.
Here are direct links to the figure images:
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Magnetic disk drives have been at the heart of computer systems since the early 1960s. They brought not only a significant advantage in processing performance, but also a new level of complexity for programmers. The three-dimensional geometry of a disk drive replaced the simple, linear, address spacetape-based programming model.
Whatever happened to cylinders and tracks?
Traditionally, the programmer's working model of disk storage has consisted of a set of uniform cylinders, each with a set of uniform tracks, which in turn hold a fixed number of 512-byte sectors, each with a unique address. The cylinder is made up of concentric circles (or tracks) on each disk platter in a multiplatter drive. Each track is divided up like pie slices into sectors. Because any location in this three-dimensional storage space could be uniquely identified by the cylinder number, head (surface) number, and sector number, this formed the basis for the original programming model for disk drives: cylinder-head-sector access.
This raises the question: If that is how data is stored on a drive, why don't we still use that as the programming model? The answer is not an easy one but has its roots in the fact that this geometric model endured until the advent of the intelligent inter-faces, SCSI and ATA. [The IBM mainframe world used a slightly different model, allowing tracks to be written with records (blocks) of user-defined length. An individual track could have sectors of different sizes. As one who programmed count key data (CKD) storage, I can attest that it offers the application wonderful flexibility, but the drive design challenges have relegated it to history. Also, a purist might point out that standards etiquette calls for SCSI to use blocks and ATA to use sectors, but I will use these terms interchangeably.]
Disk-interface protocols implement the programming model for disk drives. The earlier drive interfaces did little more than expose signals to let the host directly manipulate the drive mechanism and initiate a transfer of data at a target location. This put the task of dealing with all the low-level idiosyncrasies peculiar to drives on the programmer charged with developing the firmware or software support.
The introduction of ATA and SCSI fundamentally changed this. Table 1 describes the migration of intelligence from host to drive in the evolution of the more important interfaces. With these intelligent interface protocols, the task of programming the use of disk drives became much easier. Disk-drive designers also gained a freedom of action needed to design higher-capacity and higher-performance drives. I will look at just how drive designers used this freedom of action in their designs, but it is important first to understand the fundamental goal behind drive design: increasing areal density.
DAVE ANDERSON, director of strategic planning for Seagate Technology, has more than 20 years of experience in the computer field. His responsibilities include overall strategy for all disk interfaces. He has been involved in the architecture and planning of Fibre Channel since it was first proposed as a disk interface. He was also one of the principal architects of the disk XOR commands that are now a part of the standard
Good article. Pity the website is so fucked that you can only read half of it.
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Of course... typical php site.
And I hear that the GameCube is region sensitive, so if you're in the southern hemisphere and playing a game, it'll start spinning the discs counterclockwise so the coriolis effect doesn't interfere with the 'natural' spin of the GameCube. Nintendo really pays attention to the details like that.
Who the heck modded this idiot up anyway? Sheesh. First, it's not a CD-ROM. Second, it doesn't spin backwards. I have a GameCube, and all you have to do is pop the top open while there is a disc in it. Viola -- it spins clockwise! Another urban legend debunked through the use of common sense and experience.
The whole price system for internet broadcasting should be NO DIFFERENT from traditional radio broadcasting.
They should be paying us.
Reminds me of 6 of the 12 computer science hours I took last semester; an informative article nonetheless and a good read for those who.... thing about that stuff a lot. I was sure that my programs ran around inside my harddrive fighting bigger three-letter acronymed programs.... oh well, my dreams are stamped out yet again by Dr. Science and his cronies.
how is this informative?
CD players are AUDIO, the beginning of the album is always written in the centre, the end of the album always at the edge. so obviously playing from outside-in would result in music being played backwards.
Whoever wrote that is obviously making this up and has no idea how CD's work.
And the words disc and disk are interchangable. If you want to get technical, the gamecube uses a mini DVD, which officially stands for "Digital Versatile Disc", not disk.
Any readers not already aware of the deathstar gxp drives designed and manufactured by IBM, and now a Hitachi/IBM product, should check out the links.
And immediately after reading the articles, should backup, get one or more new drives by another company who stands behind their products, and use the current deathstars as additional swap drives if you can afford losing the drive, or just dump it.
And you should seriously question any hardware articles you read from any tech review site who has intentionally kept their head in the sand on this issue, even after being alerted to the issue at the height of the storm.
Are you listening, t**?
in soviet russia...
*ducks_and_hides*
the computer is online
i am not at it
what a waste of ressources
They get bigger, they get faster, they get quieter. Everyone wants a bigger, faster, quieter one. What else is there to know?