Mitsubishi Mf355f-592ma Manual Inject Floppy
Apple 661-0474 Floppy Disk Drive. The first model of Apple’s SuperDrive. This 3.5″ floppy disk drive has no door and is “auto inject” (or auto insert or auto feed where the disk is pulled in once inserted far enough) and used in most 68K Macs (Note that the Plus or earlier used a 400K or 800K drive and cannot use this). Late 68K machines may also use this drive, but the cover, case or bezel will differ between “auto inject” and “manual inject”, so they are not interchangeable. The last photo shows two LC III’s, the top is auto inject and the bottom is manual inject – note the location of the eject hole as well. All are made by Sony, 2MB, Model MP-F75W-01G (02G, 12G, etc), but all start with MP-F75W on the blue label. Note that these do not display any Apple identification on the drive.
These are available with or without the most common carrier or sled 805-0961-A. Carrier also sold separately. At this time, I am just trying to process stuff through and make it all available, so beyond testing, these have NOT had any maintenance performed by me.
Available as:. Nice – read, write, format and eject smoothly. Need work – read, write, format but eject is weak. They need lubed. Parts – May not initialize, may not read, will not eject, any or all issues. Product Options. Apple 661-0121 Floppy Disk Drive.
The second and newer model of Apple’s SuperDrive. This 3.5″ floppy disk drive has a black door and is “manual inject” (or manual insert) and used in all PowerPC Macs. Late 68K machines may also use this drive, but the cover, case or bezel will differ between “auto inject” and “manual inject”, so they are not interchangeable. Pictured and most common is a Sony 2MB, Model MPF 42A, but another drive sharing Apple’s same part number and completely interchangeable is Mitsubishi MF355F. You may receive either, note that these likely do not display any Apple identification on the drive.
Drives tested to format, write, read and eject easily.
I'm not really in the market, but I've seen these. a few times: www.ebay.com/itm/Mitsubishi-Apple-Macintosh-MF355F-592MA-2MB-3-5-Floppy-Drive-Internal-/81. Is this just a labeling error? (per: which references the model number as a standard manual-inject floppy drive). In other words it's just a standard 1.44mb drive and not some 2mb drive, right?.There are multiple listings (I checked just now to make sure I hadn't seen the same one repeatedly).
The second one I checked is a standard autoinject drive. 2 MB refers to the raw number of bits (in bytes) that can theoretically be placed on the disk. However, much of this space is used by sector headers and 'gaps' that let the floppy controller process data before the next sector comes up. So the resulting amount left for the users is normally 1.44mb. Some formatting tools can reclaim some of this 'wasted' space at the cost of compatiblity and speed.
Many vendors labeled their 3.5' HD floppy disks and drives as '2MB' because it sounded better than 1.44mb. The twisted marketing drones could claim the statement was 'techincally' true. To scratch an old itch, exactly what unit of measurement does 1.44MB refer to?
Consider that a '360K' drive has 720 sectors of 512 bytes. Similarly a '720K' drive has 1,440 sectors of 512 bytes. So, in this context, K = 1,024 (i.e. Now a '1.44MB' drive has 1,440 sectors of 1,024 bytes. So M = 1,024 x 1,000. What the hell kind of unit is this?
If you go with M=1024.1024, then the drive should be called '1.41 (1.406 approximately) MB'.-or just a '1440KB' drive. This was also a problem with early hard drive labeling. At any rate, MFM recorded at a clock rate of 500KHz (2 usec per bit cell) on a disk spinning at 300 RPM gives you 100,000 bit cells per track, or 12,500 bytes per track. There are two tracks per cylinder and 80 cylinders specified as useful. Therefore 12,500 x 2 x 80 = 2,000,000 bytes.
How one wants to break those bytes up into formatting information is left as an exercise; unlike the bastardized '1.44MB' label. Some 3.5' drives are '3-mode' allowing for compatibility with the largely Japanese 'NEC' convention of carrying the same format across from 8' to 5.25' to 3.5' media (a common-sense thing to do), so they can also spin at 360 RPM, resulting in a '1.6MB' drive capability. In all cases, M = 1,000,000. One of the standards for 3.5' HD floppy drives (ECMA-125) refers to the resultant device as 2MB.
Apple officially referred to their High Density format as 1.4MB; Amiga had odd scheme to go for 1.76MB; and Acorn pursued a 1.6 MB format. Toshiba even went further by increasing the number of tracks to 84 but did not advertise their 3.5' HD drives on the basis of that higher capacity. Floppies were incredibly fun as clever engineers and cunning marketeers often gave the opportunity to ensure disks couldn't be shared with other systems.
Thanks guys, appreciate the info. I figured it was something like that - and I figured it'd have been a marketing ploy. But I guess my real question was why people use that ploy now.? Who's going for high-capacity floppies now (as such - who isn't either using zip disks or maybe smartmedia adapters, or whatever - that's a narrow range of 'as such')?
Mitsubishi Mf355f-592ma Manual Inject Floppy Disk
You have to figure the only people in the market are looking for specific replacement floppies for classic machines.I think I vaguely recall having known the 2mb raw data thing from at some point in my maybe youth. But now it's just confusing enough to potentially put people off from buying replacement drives. That's an at worst; at best it serves no purpose since anyone in that market would either already know this or look it up. (.(cont'd) Honestly I just sometimes find seller strategies really interesting.
I'm also really curious why sellers advertise 'working' machines without screenshots of the booted machine. I contacted a guy who was selling an SE/30 a few weeks ago. He said he just hadn't thought of it and would put one up - let's see if he did: he sure didn't. and it still has not sold). Maybe not relevant to this thread but there was the ED disks and drives which had an unformatted capacity of 4MB, 2.8MB formatted. Yes, basically double the number of bits per track and the use of a different oxide/ferrite coating. Instead of a 500KHz clock rate, it used 1MHz.
But to answer raulduke's question, there are a number of reasons that floppies are employed. The first is universality-it's quite possible to write a floppy on a new machine (even if it uses a USB floppy drive) and read it on an old 5150. The encoding really hasn't changed. Another reason is that floppies are governed by an ANSI/ISO standard. A third is that they're cheap. A fourth is that they come from a time when a megabyte was a sizable amount of data (remember the discussion about the single-floppy bootable OS and browser that had both modem and NIC capabilities?). Zip disks are far from universal, and, in fact, the IP is owned by Iomega.
The same can be said of most flopticals as well as EZFlyer, Superdisks, UHD144 and other media. 650MB MO media died a log time ago. USB flash is making inroads, but not all legacy computers have USB and fewer can boot from them.
And floppies, if stored correctly, are remarkably robust. Whether or not a MLC flash drive will still be readable 40 years from now is something that's yet to be determined. Of course, by then, everything will be on/in the Cloud, with much of it lost forever.
Because that's industry-standard terminology. It indicates the raw data capacity of the floppy at a standard data rate and encoding, no matter how it's sectored. For example, I can take the same floppy and sector it with 256 or 1,024 byte sectors-most controllers are perfectly capable of doing that.
The formatted capacity changes, but the unformatted capacity remains the same. Have a look at the OEM manual for a common '1.44MB' drive (1/2/1.6MB stated. USB floppies have the format hard-coded, so they are an exception, but a standard 'legacy' floppy drive is a very dumb device and pretty much doesn't care what comes over the READ DATA and WRITE DATA lines. No I didn't mean why would someone being using a 2mb floppy; I meant why would sellers label their auctions '2mb'? 1) 2MB is the correct term according to the standard. 2) More is always better. 3) To remind people who have other (non-PC) systems that this floppy might work with their system as opposed to some USB 1.44MB floppy drives which only work with that single format.
Though if you think people advertising floppy drives now on the basis of the theoretical capacity, there are a number of websites where people try to prove the actual maximum data storage limits even at the expense of reliability, interchangeability, or even destruction of the drive. Up to 1.68MB formatting actually works fine in any standard 1.44 MB floppy drive. Even in Windows Xp.:) Some more is possible, but many operating systems cough up on it. Here's trial version of a tool. Only 30 days of trial, but should be enough to format a few thousand floppies.
Under DOS there were also 2M and 2MGUI which would lead to a floppy with 'nearly' 2MB capacity in a 1.44' floppy drive. However, these were generally not compatible with Windows or many other systems. I corresponded with Ciraco back in the 1990s and have one of his first beta versions in my files. The way this is done (as well as IBM XDF) is that, if you read the NEC 765 datasheet, you'd think that a disk must have sectors of the same size on a track. Fortunately, that's not true-the 'format track' command will write n sectors to a track according to command parameters, but use a table of 4-byte entries to actually, without inspection, write the ID headers.
So if a header says, for example, that the data field is 1,024 bytes, when it was formatted as list of 256-byte sectors, subsequent write commands will blindly write 1,024 bytes for that sector, over-writing a couple of other 256-byte headers. So, by keeping the gaps small, you can fill a track pretty full. I wouldn't recommend a format like this for routine read-write use, but as a read-only medium, it's no less reliable than any other conventional disk format.
Thats why both IBM and Microsoft used similar schemes (XDF and DMF). Once you've written the data and verified it, you're okay. Just don't try to over-write anything. I have a 2.4MB 5.25' IBM Floppy drive in my DOS PC.
I bought it because it was cheaper than a nice black 1.2MB on eBay, and it works just fine as a 1.2MB drive. I don't think I can use it as 2.4MB via DOS, though. Does it read the double density formats (360kB and 160kB)?
I wondered about that back when they appeared on the market. I have read usenet posts of people claiming to use the 2.4MB drive with a PS/2 to attempt to copy 2.4MB disks for use with IBM 3174. As expected of usenet posts, these are 20+ years old and completely lack any information to duplicate the process. NEC advertised a 8' 2.4 MB floppy. I suspect the 2.4MB 5.25' drives were just a drop-in replacement for that. Though that seems just as much a dead end as almost nothing remains about the NEC floppy either.
Does it read the double density formats (360kB and 160kB)? I wondered about that back when they appeared on the market. I have read usenet posts of people claiming to use the 2.4MB drive with a PS/2 to attempt to copy 2.4MB disks for use with IBM 3174. As expected of usenet posts, these are 20+ years old and completely lack any information to duplicate the process. NEC advertised a 8' 2.4 MB floppy. I suspect the 2.4MB 5.25' drives were just a drop-in replacement for that. Though that seems just as much a dead end as almost nothing remains about the NEC floppy either.
That goes for the the Hitachi and YE Data drives used by IBM as well. As I understand it, the sole use for the drive was to load microcode for the 3174. No posting I located ever claimed to be able to use the thing to write such disks. That goes for the the Hitachi and YE Data drives used by IBM as well. As I understand it, the sole use for the drive was to load microcode for the 3174.
No posting I located ever claimed to be able to use the thing to write such disks. The following Google Groups link matches what I remember finding in previous researches but it is from only 10 years ago. Completely useless since it provides hints and allusions to someone trying to use a PS/2 with these drives in 2.4MB mode but no details as to how. I found 2 Kao MF2HD disks that are labeled 2 MB Capacity. They cannot be read and cannot be booted from either. Unlike normal 3 1/2 disks light does not go through them. So are they simply 1.44MB disks that have been erased naturally by stray magnetic fields or whatever, or are they special disks that cannot be used with a 1.44MB drive?
I ask because light does no go through them, so they are definitely made from different materials than normal 3 1/2 disks. In 1986, Kao was making the MF2HD as a thin disk at 720 Oe which became the official standard for High Density disks.
It is most likely that you have disks that were never formatted though bad disks have slipped out of the factory before. They have scribblings on their labels so they were definitely used before. If all disks labelled MF2HD ever made were all the exact same thing then those Kao disks I found were simply naturally erased. But I think this is the first time I see a 3 1/2 magnetic disc that blocks every bit of light shining on it.
Usually discs glow orange-brown when light shines on them or dark brown. I bet if I covered my windows with these Kao magnetic discs then my house would be pitch-black.
Not impossible that Kao sent a batch of double density cookies through the high density line or made a change to the formulation. I doubt I could figure it out even with pictures. What OS are you using to format these disks? Some are reluctant to format over unknown formats and some backup software made quite strange formats.They cannot be read and cannot be booted from either.
Are you certain about the format used to write them? For example, I have a pile of 3M DSHD floppies that were written in a Brother word processor. The Brother normally uses DS2D floppies and writes its own peculiar format (i.e. Not DOS, not Apple anything, Brother-specific). Naturally, they can't be read on a standard machine, be it IBM, Apple or Commodore Amiga.
But the coercivity of a DSHD is close enough to that of a DS2D, so it doesn't matter-the Brother is 'blind' to the density-indicator hole.