# 'THINNEST EVER' spinning terabyte beauty slips out of WD fabs

WD says it is shipping the thinnest terabyte drive ever, giving thin and light notebook suppliers and users 143GB of capacity* per millimetre of drive thickness. The WD Blue drive is 7mm thick (0.28in) and has, we understand, one or two 500GB platters inside it depending on the capacity levels offered – these range between 250GB …

It's nice for laptop manufacturers, but a 7mm drive in a "standard" 12.5mm bay is just wasted space, so it doesn't make sense as an upgrade for people with existing laptops. What could they have done with a standard height drive I wonder....

#### However

The majority of lightweight laptops, PS3's, slim USB enclosures, etc use 9mm height, so no manufacturer in their right mind is going to alienate themselves from this lucrative market.

#### Re: It's ok... BUT

*BUT most people prefer SSD drives anyway..*

I might *prefer* an SSD, but I'd have trouble convincing myself to *pay* for one of that sort of capacity until they drop in price by another factor of five or so.

It's good that manufacturers are continuing to improve the range of spinning rust devices, providing higher capacity drives at affordable price points ... now where's my 8TB desktop drive?

#### iPod Classic update?

I know it's not cool to own an iPod these days but personally I find the 160GB storage of the iPod Classic to be really handy. I've stuffed mine with TV shows and films find it very useful when going on holiday, but 160GB just isn't enough for a particularly high bit-rate.

An iPod Classic with 1TB of storage would be perfect for that sort of job...

Well, the HDD (or other storage manufacturers) started to make a mess of things a long while ago. All in the concept of clarity, or maybe just sales and marketing lies...

The two sets of figures are now clarified in parallel - the base 10 (1TB = 1000GB, 1GB = 1000MB, 1MB = 1000K and so on) and the base 2 (1TB = 1024 GB).

So when a HDD manufacturer quotes a capacity in TB the total number of bytes compared to what they put on the packaging and what you might expect can be quite different as they'll use the base 10 values and if you're using the base 2 then you're going to be quite annoyed...

"1 TB = 1000000000000bytes = 1012bytes = 1000gigabytes. A related unit, the tebibyte (TiB), using a binary prefix, is the corresponding 4th power of 1024"

http://en.wikipedia.org/wiki/Terabyte

It's on Wikipedia so it must be true.

Seriously though I recall (or was told) that binary power description for capacity stops at MB and then goes up in 1000's.

@ravenviz

Nope. Strictly speaking megabyte, gigabyte, terabyte, exabyte, petabyte, etc, are all powers of two. The only people who disagree are selling mass storage, either spinning rust or flash memory based.

Scientists will also disagree, because M G T etc. are SI prefixes defined as powers of ten. The correct prefixes for 2^10 2^20 ... are indeed ki, Mi, Gi, Ti, ...

A 4k7 resistor was 4700 Ohms, and a "megohm" resistor 1,000,000 Ohms, before the word "byte" had been coined.

@An0n C0w4rd

I'm afraid you're wrong. While computers do use binary and powers of two, SI units do not, as Nigel has already pointed out. This is why a kilometre is not 1024 metres, a tonne is not 1,048,576 grammes, and so on.

It's interesting that nobody complains that their 1 GHz CPU runs at a billion Hertz (using short scale powers of ten, in case you want to get pedantic) and not 1,073,741,824 Hertz (that's nearly 74 MHz you've been short-changed)

It pisses me off immensely that we use powers of 10 to sell storage, especially when computers are inherently binary, but "strictly speaking", we're lumbered with it. It's not about whether you disagree or not. It's a standard and therefore can't be changed. It's just an arithmetic coincidence that 2^10 is roughly the same as 10^3, but not quite.

#### Strictly?

*Strictly speaking megabyte, gigabyte, terabyte, exabyte, petabyte, etc, are all powers of two.*

No **strictly** speaking those are measures of storage capacity, not powers of anything.

Strictly speaking, the prefixes mega, giga, etc., indicate multiples that increase in powers of ten (every third power, in fact, so the series of units so described increases in steps of factors of a thousand).

**Loosely** speaking, we IT people tend to misuse these prefixes to indicate multiples that increase in powers of 2 (every tenth power, so the series of units so described in steps of factors of 1024) -- and get annoyed when the disk manufacturers try to fool us by using the strictly correct meaning.

The correct names for the binary prefixes are mebi, gibi, etc., as described at:

http://physics.nist.gov/cuu/Units/binary.html

#### Sigh

1TB = 1000GB, 1TiB=1024GiB. Unless you are measuring memory, where the context strongly suggests a power of two, there is no reason to assume anything other than a power of 10 is meant by an SI prefix.

#### Re: Sigh

You're right, and in pedant-land that is completely true, but in the real world, everyone is still working with powers of two when they refer to KB,MB,GB,TB etc. Maybe I'm just unlucky, but I never see MiB in day to day use, and I've never, ever heard anyone say "mebibyte" out loud (am I the only one?).

#### Re: Sigh

In most contexts the two are close enough to be treated as ~equal. In software documentation concerning (mostly) disk partition tables and related entities, they take care to get it right. Often, command lines use abbrteviations m for 10^6 and M for 2^20, rather than M for decimal and Mi for binary, but the documentation spells it out.

We need to stop letting HD manufacturers use weasel-words to short-change their customers. I'll go with base-ten drive measurements when they also start giving bytes ten bits...

#### I can't believe people consider this debatable.

Which method of measurement matches the abbreviations used in every other area of science?

Which method of measurement unnecessarily complicates every single bit of math?

#### Re: I can't believe people consider this debatable.

Powers of Two are applicable to RAM and ROM as addressing and storage increments are binary.

Drive storage, communications Bit Rates, Frequencies etc are all correctly powers of 10.

I can't believe that after over 40 years some people are STILL trying to argue that the "short hand" & misleading method of counting in 1024 increments (because a 1K RAM was 10 address bits and thus really 1024) is correct for anything else when it was only ever a convenience for chips and address buses.

I don't need to use Mebi etc. If it's chip related I know 1024s apply. But MHz, GHz, M bps, M symbols/s, disk storage, Kilometres etc are all powers of TEN not powers of 2.

Anyway I look forward to a future new laptop with 2 of these mirrored.

#### Of Terabytes and Gigabytes

When using these items, does anyone actually notice the difference? Of course that is other than when the windows graphic has a number below it?

Yes, a Megohm was 1,000,000 ohms, and a Megahertz was at 1000 on the AM dial (maybe 10, or 100). Us computer types seem to have gotten into a habit of thinking that 2^10 is 10^3, which while "close" (various technologies differ on this!) isn't exact. We just hate to recite long numbers.

Of course when someone said 20k for the memory of an IBM 1620, they really meant 20,000!

#### It will be fun after we pass 10^51

which is midway between 2^169 and 2^170. I suspect our machine descendants will have finished arguing by then.