THe price of wood

[Mike Marlow]

Yup - my background also.

I've never seen the asterik, but I've never looked for it. There is overhead on a fresh drive though that does eat into the capacity. There is a low level format that is beneath the level of the operating system. Then there is the filesystem you're refefring to. I guess I'm not familiar with today's marketing practices, but it used to always be that the unformated drive capacity is what was advertised and that was before the low level format - what we used to call the hardware format. Then you put the filesystem on top of that and lost even more capacity. Today you put microsoft products on top of that and lose all of your capacity...

It's easy enough to figure the real capacity though. Number of bytes per sector multiplied by the number of sectors, and the number of cylinders. I suspect if you do this on any disk drive it will not come out to an even MByte or GByte count.

It is a rewarding feeling, isn't it?

[LRod]

Back in 1999 someone wrote a question to a local newspaper inquiring why the upcoming click-over to 2000 was called Y2K when every computer literate 12 year old knew that a "K" was equal to 1028 and thus everyone was apparently celebrating 2048. You would not have believed the answer. (paraphrased; don't remember it exactly) "the 2048 is 'averaged' to 2000 so that Y2K makes sense."

Who'd have thought that the clueless pendulum would have swung so far so quickly and to include so many, beyond that which one would expect.

I wrote an erudite reply regarding scientific/mathematic suffixes and prefixes and their predating computers by some decades that was probably digested solely by the immediate members of my family who were fairly bulldozed into reading it.

- - LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

[Brett A. Thomas]

Since we went from MFM to IDE, nobody low-level formats anymore. Now that the controller doesn't have to have intimate proprietary knowledge of the drive, you don't need to low-level format. In fact, on most machines, you can't, anymore. What you're saying was true a long time ago, but it's not the reason for discrepancies, anymore. See this page from Seagate, for example, on "Discrepancy Between Reported Capacity and Actual Capacity,"

says, among other things, "Unfortunately there are two different number systems which are used to express units of storage capacity; binary, which says that a kilobyte is equal to 1024 bytes, and decimal, which says that a kilobyte is equal to 1000 bytes. The storage industry standard is to display capacity in decimal."

See also, for example, this stat page on a random Seagate 160 GB drive:

you click the "capacity" link on that page, it sends you to:

says, "Capacity is the amount of data that the drive can store, after formatting. Most disc drive companies, including Seagate, calculate disc capacity based on the assumption that 1 megabyte = 1000 kilobytes and 1 gigabyte=1000 megabytes." So, they're explicitly saying that it is a post-format size, so that's definitely not the issue. The issue is that they have a definition of "gigabyte" that is completely different from the rest of the industry, including the sizes reported by the computers that use the drives.

Which was my point, when someone lectured me that a "K" is always 1024 - it always is except when it's not. :)

-BAT

[Mike Marlow]

We went from MFM?

[Prometheus]

That's why it's a little regret! I look at them, sigh, and think about what it would do to my bits and blades if I ran into a nail or embedded rock, then let them go.

Aut inveniam viam aut faciam

[Silvan]

Yes, thank you. You're right. I'm right.

I seem to recall that the old MFM and RLL drives actually delivered the advertised capacity. Am I dreaming that? It was a long time ago. The largest one of those I ever laid hands on was 80 megabytes, and I think it would have actually been 80 megabytes if all the heads had been working. :)

Boy, they don't make'em like they used to. My first computer that was MY computer was put together out of complete junk parts like that. The 80 meg drive had bad bearings, and it screamed like a jet engine. One or two of the heads didn't work, and it had gazillions of bad sectors. It still worked, and I used it for awhile, until I saved up enough money to buy one of those new IDE deals. A 120 MB drive that I still have around here somewhere.

More recently, I had a 40 gig (Maxtor) drive that was about 11 months old. One morning, I came in to get on the computer, and the drive was clicking. Just like that. Poof. Gone. I'll bet that damn gimp 80 meg RLL drive would still work to the same limited extent that it was working twelve years ago. Ugh. Fourteen years ago.

Wow. I knew my wife back then too. She was right around the same time I was putting that POS together. Funny how 14 years ago seems an eternity in computer terms, but just getting started on a marriage. (Well, 11 years of marriage, and three years of incredible sex. Not necessarily in that order. :)

[Upscale]

You know Silvan, I was reading this thread and I saw the above comment, and I knew right away before I saw your name, it was you making it. Your thinking on this subject has preceded you. :)

[Silvan]

On old computers or old women? :)

[Upscale]

One woman in particular. Can't say if she's old or not.

[Dave Hinz]

Er, yeah, in the 1980's, friend.

[Silvan]

Depends on if I'm mad at her or not how old she is.

[Mike Marlow]

... failed attempt at humor - or you were ducking as that one went by. You had to be ducking because it wasn't clever enough to have made it over your head on its own.

[Edwin Pawlowski]

Had the MFM! What did I miss on the IDE and should I bring a friend?

[Scott Lurndal]

This is incorrect. All drives must be low-level formatted, the IDE drives are now formatted at the factory. SCSI drives can be low-level formatted in the field, and often are to change the sector size (for mainframe systems) or other media characteristics .

The low level formatting divides a track into multiple sectors. There is some capacity loss in each track as a result of this (inter-sector gaps).

High-level formatting (e.g. DOS Format command) places a filesystem on the media (to store directories, free space lists and file metadata) further reducing the available capacity.

Disk space is allocated to files in fixed size quantities, from 512 to

8192 bytes per chunk depending on the OS and filesystem. A lot of 100 byte files will waste 412 bytes per file (so you could realize perhaps only 20% of your stated drive capacity before "filling it up").

Stated drive capacities are best considered approximate.

scott

[Robert Bonomi]

NO, you are _not_ dreaming it. A ST-225, commonly referred to as a "20 mb drive", had a _formatted_ capacity in excess of 21 million bytes. "Usable" space, after a filesystem was laid down, was a fair bit lower.

[Brett A. Thomas]

That was an MFM drive. Believe it or not, Seagate still has a tech reference page up on it:

they haven't retroactively changed their literature to correspond to their current (wrong) numbering scheme, here're their quoted numbers on it:

25.6 MB UNFORMATTED CAPACITY 21.4 MB FORMATTED CAPACITY (17 SECTORS)

But, let's remember, *terminology* has changed since then. Back then, "unformatted" meant "not-low-level-formatted." "Formatted" meant "low-level-formatted but without a filesystem on it." Nowadays, your IDE drive comes low-level formatted, so if you want an apples-to-apples comparison, you want to look at today's "new-in-box unformatted" hard drive capacity versus yesterday's "[low-level] formatted [without a filesystem]."

In that page, they state it had 41,820 sectors per drive. Assuming it followed the standard of 512 byter per sector, that'd be 21,411,840 bytes, or 20.42 (real) MB. So they're quoting "21.4 MB" as the capacity, but we can clearly see that's actually only 20.42 *real* MB.

So, sorry, guys, you're engaging in that classic pastime of remembering the past as better than it was. They started lying about hard drive sizes a *long* time ago, it was just harder to tell with the unformatted vs. formatted confusion. Also, when you put a filesystem on it, you inevitably lose some space. Since they were quoting 21.4MB but you were only getting 20.42 MB, but you didn't see that until FAT had eaten another chunk, so it wasn't real obvious that you were losing that much.

Anyway, maybe the reason it was "commonly referred to as a '20 mb drive'" is because it *was* a 20 MB drive. ;)

-BAT

[GregP]

We were dealing with variations in capacity data more than 20 years ago. They are largely the artifact of "generic" drives, drives that can be used with various systems, and thus potentially formatting in unpredictable ways. In the good old days of proprietary systems, you could buy drives that had accurate specifications.

[Robert Bonomi]

Your assumption *IS* in error.

The early datasheets -- like the paper one I have in my files -- listed numbers 'to the byte', not the 'approximations' cited below.

Yup. your assumptions, and numeric derivations are accurate. That is precisely why it *was* known as, and *sold* as, a "20 mb drive".

Bullsh*t. there were *MANY* 'readily available' utilities -- including the formatter that was BUILT-IN in the HD BIOS chip -- that reported the 'raw' formatted capacity in actual bytes. And short-hand forms using 1024*1024 multiples.1G

No shit, Sherlock. It _was_ the standard 'way back then' to describe disk- drive capacity in units of 1024*1024 bytes.

Then the marketing guys got into the act, and perceived an advantage to rating disks in 'millions of bytes', when the competition was sizing in '1024*1024' bytes. With disks in the 10e8, and above, capacity range, the 'paper difference' was enough to be a 'marketable difference'.

It did make apples-to-apples comparasions *difficult*. What was worse, the same manufacturer would use different measurement styles on different lines of drives.

This was particularly comical, when it was the _same_ HDA assembly, just with a different controller card on the drive.

[Rick]

Until you slapped that puppy on an RLL controller and made it a 30 MB drive (give or take a few kB).

Of course, if you were a gambling person, you'd then doublespace the drive for 60 MB (or so) per ST-225.

Like it so nice? Do it twice!

And ... if you were REALLY LUCKY (as I was ), you replaced the pair of ST-225s on said RLL controller with doublespace installed (120 MB) JUST before it died. Died is defined as you just ran the last QIC tape and when you rebooted ... nothing happened. Load the new drive with DOS and the tape utilities, restore, and away we go ... back in business.

Woodworking is mild in comparision.

Regards,

Rick

[Swingman]

Damn, how soon we forget. Your use of the word "Doublespace" suddenly brought back a flood of memories of words/terms like "Stacker". "DriveSpace", and "CVF" that I guess had slipped into my subconscious. Who was it sued MSFT for stealing (what else is new) their compression algorithm, Stac Electronics, or something like that? IIRC, that was a BIG deal when DOS 6.0 came out.

Time really flies ...