The First Terabyte Hard Drive Reviewed

mikemuch writes "ExtremeTech has a review and benchmarks of the Hitachi Deskstar 7K1000 1TB Hard Drive, which ushers in the terabyte age. It performs well on HDTach and PCMark benchmarks, though not as speedily as professional-grade drives. It could be just the ticket for digital media junkies. 'One of the first issues to note is that you may not see an actual one terabyte capacity on your system. First, the formatted capacity is always less than the raw space available on the drive. Directory information and formatting data always take up some space. Second, the hard drive industry's definition of a megabyte differs from the rest of the PC business. One megabyte of hard drive space is 1,000,000 bytes: 10^6 bytes. Operating systems calculate one megabyte as 2^20 bytes, or 1,048,576 bytes. Once installed and set up, Hitachi's 1TB hard drive offers up an actual formatted capacity of about 935GB, as measured by the OS. That's still a lot of space, by anyone's definition.'" Update: 05/17 21:52 GMT by Z : Adding '^s' missing from article.

Comments

Now I need faster broadband

[Anonymous Coward]

So that I can fill this new drive with pr0n ;)

New New Math?

[WrongSizeGlass]

One megabyte of hard drive space is 1,000,000 bytes: 106 bytes. Operating systems calculate one megabyte as 220 bytes, or 1,048,576 bytes. That was from TFA (not just the summary). I asked my calculator about that but it just got a headache.

Why is this still a discussion?

[Grelli]

Don't complain about the fact a megabyte isn't what you thought it was. Complain about the fact the industry still uses it for labels. But don't try and make the megabyte a mebibyte.

http://en.wikipedia.org/wiki/Binary_prefix vs http://en.wikipedia.org/wiki/Si_prefix

Re:Why is this still a discussion?

[jdgeorge]

Don't complain about the fact a megabyte isn't what you thought it was. Complain about the fact the industry still uses it for labels. But don't try and make the megabyte a mebibyte.

What!?! Next thing you'll be telling me is that a kilometer isn't 1024 meters long. Please, stop this madness before it spreads!

Re:Why is this still a discussion?

[blhack]

We could just simplify the process and start calculating drive space in libraries of congress * elephants of pressure per square postage stamp.

Re:Why is this still a discussion?

[dgatwood]

They are still wrong. The fundamental organization of computers is base 2. Ever try to design a processor that uses 1000 byte pages? Good freaking luck.

The purpose of SI units being in base 10 is because the number system that we use to measure things is ALSO in base 10. Therefore, the unit fits comfortably within mathematics associated with the relative fields. However, A base-10 numbering scheme basically does not exist in the computing world; obscure BCD hardware notwithstanding, all occurrences of base ten in computing are entirely a fiction created by the machine to try to make things more understandable to people used to base 10.

More to the point memory and storage are inherently organized in units of powers of two. Memory will ALWAYS be organized in power-of-two increments as long as computer operate based on the binary system. Why? Because this makes it possible to express divisions of memory in terms of bit boundaries. A power-of-10 memory organization would require computationally heavy division or multiplication operations throughout the memory management code, while a power-of-2 memory organization requires an extremely lightweight bit shift. For this reason, as long as we have binary-based computers, we are stuck with power-of-two units of RAM.

Similarly, a hard drive block will ALWAYS be evenly divisible by the size of a memory page or vice versa. If this were not the case, the complexity of writing an operating system would be beyond insane. Paging and memory mapping of files alone would be enough to make the engineers commit seppuku. Therefore, as long as RAM is organized into groupings based on powers of two, hard drives will always be physically laid out in blocks whose length is a power of two.

Because the fundamental organization of data in a computer is, by nature, organized into power-of-two units, describing storage in power-of-ten units makes no sense, as it will almost always be a crude approximation. There are probably exactly zero hard drives with an exact decimal gigabyte capacity. The fundamental storage in hard drives is a 512 byte block, and 512 does not divide evenly into most multiple-of-ten values. Sure, you could create a 512 decimal gigabyte drive, I suppose, but for the most part, the values just don't divide evenly by 512. Therefore, using a multiple of a power-of-ten number to describe the amount of storage will almost always be a very crude approximation, while using a multiple of a power-of-two number can be (and usually is) an exact value.

In other words, the idiots in charge of making up the SI units should have been taken out and beaten for "Gibibyte". There is one natural unit in computers, and that is the base-2-derived gigabyte. All base-10 units are inherently inaccurate, and thus a poor fit for computing. They should be summarily rejected by the industry, as they simply do not make any sense in the context of storage. Honestly, they don't make a lot of sense for networking, either for the same reason, but I'm willing to overlook that... for now....

Re:Zonk

[OrangeTide]

It's not a race Zonk, you can hit the preview button once in a while.

From this day forward all badly formed posts shall be known as Zonks.