Put 1.7MB onto 1.44MB Floppies (1999)
trevormarshall.com
trevormarshall.com
But sectors are 512 bytes to make it easier when dealing with the actual nitty gritty of reading data?
It isn't completely disingenuous to talk about intra-systems communication in terms of 'million bits' (engineering mega, not binary 'mega', bits) but it is obtuse and full of marketing spin.
Maybe you're thinking of 1GiB?
They do, but that's not what diskettes did. Hard drives use KB = 1000 B, MB = 1000 KB, etc. as units. This makes the number on the side of the packaging larger, so it's good for marketing. They used to use 512 B sectors internally. (Today, HDDs have moved to 4 * 1024 B sectors, or 4 KiB, I believe.[4])
([1]) 3½" diskettes were 1474560 B (1440 KiB). If we use the programmer's "KiB", where 1 KiB = 1024 B, 1 MiB = 1024 KiB, we get 1.40 MiB. If we use the marketer's 1 KB = 1000 B, 1 MB = 1000 KB, we get 1.47 MB. The only way to get that 1.44 number is to mix the two: 1474560 B / (1024 B / KiB) / (1000 KB / MB). This is of course utter nonsense. But I guess it got to a point where it would be weird, I guess, to not label your packaging as "1.44 MB", and so it was, until the USB drive killed diskettes[2]. (This mix happened because the size was "1440 KB", and from there, someone moved a decimal point without understanding why that didn't make sense.)
[1]: I'm going to use the binary SI unit prefixes (https://en.wikipedia.org/wiki/Binary_prefix) for clarity, but back when diskettes where popular, 1024 B was notated as 1 "KB", and it was up to context to determine if the author meant 1024 B or 1000 B. The binary prefixes didn't exist until '98, let alone were they adopted, and diskettes would die a quick death soon after that.
[2]: Or CDs, if you had a burner. Or Zip drivers or Jazz drives if you did that.
[3]: The "1.44 MB" storage device was rigid. It wasn't floppy in the least. It was a diskette. The 5¼", that was floppy.
Cut them open? - this will also explain why they were called disks/discs, even though they are decidedly rectangular...
The storage media was floppy; all “floppy disks” were fairly rigid (though the 3.5” moreso than the larger ones.)
> The 5¼", that was floppy.
The case? Not really. Neither was the 8”, though they were less rigid than the 3.5”. The actual media was on all of them, and is what the term referred to.
Language inherently is; I was talking US English where, to my knowledge, they all originated.
https://www.pcjs.org/disks/pcx86/drives/
A 5MB drive contains 5326848 bytes, or 5.08 binary megabytes. The 10MB one has exactly twice that, for 10.16 binary megabytes, and the 20MB one has even slightly more than twice, owing to more than doubling the number of cylinders (from 306 to 615), at >20.4 binary megabytes.
I think there must've been some sort of agreement between HDD manufacturers after they settled on decimal sizes, to never again use the binary ones, since otherwise one of them could start creating and advertising drives "now with real gigabytes" or "bonus capacity" to one-up the others --- the difference between a binary and decimal terabyte is 99,511,627,776 bytes, or very nearly the size of a "100GB" drive and definitely not anything like an insignificant rounding error, but in terms of the physical media adding those extra bytes to a drive would probably not be that difficult; a small increase in density, much smaller than that caused by moving to the next highest density (per platter).
Agreeing a standard does not necessarily imply evil conspiracy! If you look at the specs of drive that simple quote bytes. The rounded numbers are marketing, as much by the resellers as the manufacturers.
It's not "cheating" to use standard base-10 SI unit prefixes. Words like "mega" were in use centuries before PCs and have a well defined meaning. Networking rates are all discussed in base ten and nobody complains about those. Megapixels are base 10 as well. It is not merely tolerable, but is in fact more correct, to use decimal prefixes for computer storage.
I believe this old meme about dishonest hard drive manufacturers is a ridiculous conspiracy theory and insistence on binary prefixes for storage is a form of linguistic hypercorrection.
All file sizes everywhere we look are reported using binary prefixes. That's why people say the HD manufacturers are dishonest. It's a fair point of view.
For some parts powers of 2 will still work best, and the dividing line will probably always be arbitrary.
Pages will be 4KiB. For the few engineers who care.
I.e., a binary address bus of 16 bits in width can address 2^16 different memory cells, which is 65,536 individual locations. To make this a 'decimal sized' memory would require either ignoring 5,536 possible addressable locations, or using bus lines that are not binary. Ignoring addressable locations does not maximize the usage of the available numbering system, and building ten value electrical bus wiring in hardware is a significantly much more difficult engineering effort than building two value electrical wiring (because two value electrical wiring is simply "on" or "off").
This is why so many of the "computer units" that were close in size to the standard SI units were measured in powers of 2 sized values instead of powers of 10. Computer hardware is using binary numbers everywhere, and powers of 2 are simply the natural outgrowth of that usage.
It was humans that decided that 2^10 (1024) was 'close enough' to the SI k to call it a "kilobyte" and that 2^20 (1,048,576) was 'close enough' to the SI m to call it a 'megabyte' and so forth.
However, I stand by my disapproval of bleeding that into the consumer space, especially for files and hard drives. As you said, power of 2 is a hardware detail. Not something that end users (should have to) care about.
Base-2 is the natural order of digital computer organization. Deviations introduce unnecessary complexity. Unnecessary complexity is a form of inefficiency. And markets tend to not tolerate inefficiencies for long...except when marketing can bullshit its way in getting ignorant consumers to pay out more for less.
I side with HDD manufacturers: binary format is arcane and pointless. We should stop using it in software, too. Not start using it on drives.
Modern networking rates pay hommage to the days of analog communication systems whose rates were measured in units baud, which adheres to SI rules; the imperative relationship here is time, which also adheres to SI rules. At today's scale, these are understood to be notional approximations. Even if Joe Average had the means to precisely measure throughput, who's really going to make a huge stink with all the overhead and uncertainties that exist in real-world networking?
Computer memory is physical and different. If a computer says a file is 1.42 MiB and Joe Average can't copy it to his "1.44 MB" diskette because it's too large, you don't have to be a computer scientist to be batshit annoyed by the antics of marketing.
> Megapixels are base 10 as well.
So? Whether we're talking about a physical display or digital picture, resolution doesn't have any inextricable relationship with computer memory.
> It is not merely tolerable, but is in fact more correct, to use decimal prefixes for computer storage.
Absurd. Digital computers are fundamentally base-2. No amount of marketing quackery can change that. The first week of a freshman course in digital logic is all that's needed to dispel such nonsense.
Because that is how things have always been measured. There is no big conspiracy to con us on drive size.
Storage measurements like comms rate measurements and other scientific measurements are in 1,000s.
Programmers and some types of system engineers found it more convenient to work in powers of 2 and 2^10 is conveniently close to 1000 so the redesignation of what K (and M, G, etc.) meant just sort of happened for us. We are the oddity, not the drive manufacturers.
People first made a big noise about it (that I heard) around the time 40Mb hard drives were common place. They were stealing nearly 2 whole megabytes! I knew someone who swore blind he had smaller drives (of the 10 & 20Mb range) that were officially counted in 1024*1024s in their documentation, but the proof he was going to show me never materialised.
Flash memory is a bit of an oddity --- early drives with SLC flash had true binary sizes (although the flash itself actually had extra capacity on each sector/page for error correction), then later MLC/TLC/QLC flash required so much extra error correction data that the drive sizes went down and coincidentally became close-to-decimal, despite the fact that a lot of solid-state media is still sold in binary sizes (or small multiples) --- 4GB, 8GB, 16GB, 80GB (5x16), etc. I have a 16MB USB drive that truly contains 16,777,216 bytes (unformatted).
Apparently SD cards have dropped below even the decimal sizes(!) that a "32GB" one may contain less than the 32,000,000,000 bytes which an HDD should have:
https://www.eevblog.com/forum/chat/reduced-capacity-on-sandi...
The proof of early drive sizes being in binary is here: https://news.ycombinator.com/item? id=19589230
I know it wasn't unheard-of for hard-drives and other large storage (tapes etc.) to be measured/sold in binary units, but I'd say it was most common by the time that the public at large cared at all what a hard-drive was for them to be measured in 10^3s. There was also the concept of formatted and unformatted capacities, which is not presented to users these days (the drive in my old IBM XT was 13MB unformatted, an odd figure in both binary and decimal units).
Floppy and disc-cartridge formats were a bit of an odd mish-mash, often even mixing 10^3 and 2^10 units.
Flash was usually measured in 2^10s early on as partly as it was thought of more as non-volatile RAM than anything else and partly because it was manufactured that way. And as you mention, modern ware levelling and bad sector masking means that there will be a difference between visible capacity and actual chip capacity at which point it becomes difficult to predict what any particular controller can be or will be configured to do.
Getting less than the decimal amount might miff me a bit, but if making images it has always been best practise to drop a couple of % in volume size to account for one drive not having quite the same exact size as another. The same best-practice recommendation holds for volumes for RAID too: always limit the size to a little smaller than the maximum (either by using a partition as the block device or (if supported) telling your RAID controller/software to make the volume artificially smaller) in case your replacement drive when one fails in X months/years time isn't quite the same capacity.
One feature of floppy disks is that the recording technology and the format is independent from the physical medium, the limitations are mostly imposed by the disk drive, the encoding and the file system, not the medium itself.
Well, this "feature" creates significant compatibility issues as all the vendors created their own proprietary formats, sometimes with patents. As a result, together with the economics of scale, often, the standard format is not the best design, a simpler design that serves as the lowest common denominator.
On the other hand, due to this feature, it was already possible to store 1,760 KB of data on a 3-1/2 inch HD floppy on a 1986 Amiga. And in 2000, it was possible to store 32 MiB of data on a standard 1.44 MB floppy disk, by using a SuperDisk LS-240 drive (although random write is sacrificed, the entire floppy must be rewritten if a change is needed, like CD-RWs).
I believe the advancements in magnetic recording technology in the past 20 years allows one to achieve even higher capacity on a standard floppy, and it can be as cheap as early floppy drives if mass produced, only that it doesn't make sense to do so.
Can you name the 1986 Amiga model capable of such a feat? Because Commodore never made HD floppy controller, and the only HD capable Amiga (4000, 1992) had modified drive spinning at _half_ speed.
I hate floppy disks with a passion (ugh, installing OS/2 was a pain), but I also miss them.
Also recall installing AutoCAD 12 on 22 lab PCs from floppy... that was the opposite of fun.
```just a word of warning, copy everything off them quick, as the 'side2' goes backwards to the cotton cloth cleaner inside the 5 1/4" case, so basically all the crap caught in it then end up coming out when playing other flip side :('''
One could even do a single-sector disk, spiraling it around to avoid sector gap overhead.
- 4/5 do not work anymore
- 1/5 is this marvel of 90's design : https://www.grsoftware.net
Enjoy :)
Hmm, professional indeed.
What percentage of floppy disk readers actually implement the write protection in hardware?
The author's friendly attitude was one of the things that got me into free and open source software. Thank you Charles!