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The subject matter of the "SuperFloppy"


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#1 ispy

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Posted 09 September 2008 - 02:12 PM

Greetings folks :huh: ,

Super floppies - what are they & what are there limitations!

What do we mean when we say "Super floppies" they could means in terms or context of a hardware device a zip drive http://en.wikipedia.org/wiki/Zip_drive LS-120 http://en.wikipedia.org/wiki/SuperDisk or perhaps this definition may be more applicable.

Definition of: “super floppy“

(1) Referred to a high-capacity floppy disk, when floppies were evolving with greater storage. In the early 1990s, the “Floptical” was the first super floppy drive. Later, the Zip disk fell into that category. See Zip disk.
(2) An earlier 3.5" floppy disk introduced by IBM that held 2.88MB. The drives were compatible with standard floppies, but were not widely used.

More recently I have heard a reference to a pen-stick being called a super floppy, well perhaps an indirect reference anyway:
Boot USB-Flash in Superfloppy or USB-ZIP emulation mode. See here http://flipsidereali...emulation-mode/

When we think of floppies we immediately think of the standard 1.44Mb or the old "Super Floppy" disk drives 2.88Mb (a rare beast usually set up as drive B:\) other variant sizes existed ranging between 360Kb's 5.25 & 2.88 http://www.pcguide.c...tSummary-c.html

These would fall into hardware fixed sizes or sizing!
The next area of definition, I would classify as Virtual "Floppies/Superfloppies" these are software based & use image files from hard drives or ram disks & then there is the term "floppy emulation" using in the main 1.44Mb floppy image files to boot CD's, also not forgetting "Eltorito," sounds like a "Big Mac bar”, "Lets eat out & get a Big Mac at Eltoritoes".

In respect of Boot media most would conform to the standard hardware sizing specification each having reported varying degrees of success in their respective booting that is!

I find the whole concept of Virtual "Floppies/super floppies" quite confusing you cannot see & touch them but they are there in "ones" & "Zero's" binary format. To add to the confusion I believe that non-standard sizes of virtual floppies or perhaps more accurately varying image file sizes are being reported e.g.
http://www.wolfgang-...cdw/index_e.htm & in particular here http://www.wolfgang-...w/imgmake_e.htm and here http://www.wolfgang-...dw/images_e.htm

These images seem to be Fat image files, and how do I know this because of this comment:
All images on this page use components of the FreeDOS operating system (FreeDOS Kernel and FreeCOM), which are distributed under the GPL-license (license text, source code: FreeDOS Kernel, FreeCOM). However, these images can be amended with win-image to convert to M$ formats.

Question - the type of file structure is it fat16/32 & why is there no Image files with NTFS file structures or others for that matter:
I found this reference to putting the Ntfs file structure onto a floppy http://www.themobius...es/NtfsFlp.html
The download link is broken & only leads you back to M$oft anyway but managed to find an active link here:
http://www.ftp.plani...Disks/index.htm

However can it be used to make bootable media & can several images be made & amalgamated to form a 2.88Mb image or greater, to make a respectable sized ntfs boot image?
I also found this article: http://www.maazl.de/...o640/index.html
Now at first glance it appears to be in connection with OS/2 but reading down the page is reference to a program called
"mo640nt.exe"
& this quote:

WinNT
Normally you do not need any utility to access opticals with WinNT. However, there is one good reason for a WinNT port of this tool: if you forgot to convert a disk back before using it with Win.
The WinNT version is called mo640nt.exe and is included within this package.
· Please note that the default sector size is different:
By default the disc is converted to 2048 bytes per sector. If you have media with 1024 bytes per sector, you need the /s1024 switch.
· Do not use this utility with anything else than MO discs. Normally this should result in an error message, but it may not for other removables (e.g. ZIP).
· The WinNT version will definitely not work on DOS based operating systems like Win9x. However, it should work with Win2k (NT 5) and XP.

Is this saying that super floppies can be made from an NT ntfs system again the links are dead but have found alternatives to download?

Next question is in respect of disk geometry of both hardware & software "Super floppy" images. What is needed to make them bootable & are there any matrix tables, formula's, rules of thumb or calculations, tools to determine the required data or information needed etc. Questions relating to HDD's only having MBR's, removable media having boot sectors e.g.
Extract
Floppy Disk Geometry from the Boot Sector: http://www.codeguru....icle.php/c13809
What are the various image formats that are available .ISO. Bin, Cue, IMG, IMA, .Vfd .UDF etc etc

What’s this in context of this webpage http://www.wolfgang-...dw/images_e.htm?
Boot Cd image with a virtual floppy in drive A:
Hard disk image with 4 partitions
Hard disk image with one partition

My last question relates to the virtual tools that are capable of creating Virtual drives/Images & Bootable "Super floppy Images" or standard floppy images for that matter.
• OS/2: Works, but requires the installation of an additional operating system, which is cumbersome. The process is also non-obvious.
• Linux (dosemu): dosemu doesn't actually boot bootable games, only DOS disks or very close variants, like the bootable games that use Quicksilver's Quick DOS. And of course it requires the installation of an additional operating system.
• VMware (V8086 environment): This works well, but is a massive memory hog; we needed 64 MB of free RAM to get it to work
• Bochs (386 emulator): This has a problem with CGA emulation, and it is very slow.
• MESS and Tand-Em: PC/Tandy emulators, these programs attempt to simulate original PCs and Tandys/PCjrs exactly. They both work well, but don't support, switching disk images on the fly, write-read and write-only protection, & are old & defunct.
Essentially "Whats available, what good, what’s not"?

This whole post in a sense is not about splattering Boot-Land with input overload data but trying to learn & find answers to what are sometimes difficult questions. I for one will come clean, I know a little & in reality I have to admit my knowledge is sketchy at best. Am I the only one in the room who doesn't know this stuff?

I sometimes feel like a small child back in a classroom looking a blackboard with complex information & equations written thereon, starring in amazement & wonder, then looking around at my piers & wonder what level or understanding they have are they like me confused, or is it that I am in the wrong class?

Then the dreaded question comes from the teacher, "does everybody understand, before I move onto the next section". You think to yourself, ‘should I put my hand up or signal in some way that I do not fully understand it’, like a man placing a bid at an auction, should I, shouldn’t I? Your mouth becomes dry & your arm becomes like lead. Maybe you'll even look around the classroom to see if someone else is brave enough, but like you, are they too afraid or worse still do they in fact fully understand it unlike me, or is it that we are in, the classroom of life, a classroom full of partial understanding, a giant jigsaw.
I should have paid more attention in school!!! I see but through a darkened dimmed glass!

This subject is a very large one, with Oh so many variables it appears, a good matrix table like the projects tables, modular in design combined with hyperlinks etc would be useful, linked possibly to flow diagrams, links to pages with tutorials, guides references could be beneficial, a work in progress so to speak, networking many authors & known websites, collective knowledge, “The (Super) floppy booting Process”

Anyway this post is growing into an encyclopedia again, my motto is,

"why say a few words, when a thousand will do!"

If you were to ask me, “what is the whole point of this post, I couldn’t truthfully tell you, maybe its just to gain a better understanding re “Super Floppies” & the confusing world of the whole booting process!
To anyone who is in the know!

“My hand is in the air, Please sir! I don’t fully understand”

Regards & Respect,

ispy :huh:

#2 was_jaclaz

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Posted 09 September 2008 - 03:15 PM

Ispy,
sorry to say so, but you seem to have some "mixed concepts", you might need to use some of your patience and bear with me, with the exception of the "voodoo" that sometimes happens, almost anything involving computers has (or is derived from) some logic, very often when it comes to MS a "perverse" one :huh:, but nonetheless logic.

You must go back and take some "History of PC" classes. :)

There are historical reasons that I will try to recap briefly, users as old as I am may remember the "not so good" ol' times:
1) Once upon a time the ONLY kind of permanent storage was magnetic tape, which had NOT "Random access" features, they were Sequential and it took lots of time (and of going FF or Rev) to find where the data was
2) Then a great idea came out in the form of the 8" (roughly the size of a modern notebook) "floppy" disk, it allowed for Random Access, i.e. you could (relatively quickly) go directly to any part of it.
3) Later it was miniaturized into the once very common 5 1/4" "floppy" disk
4) Which several years later evolved again in the 3 1/2" "floppy" (which was not "floppy" anymore, but that was called "floppy" anyway)

The hard disk was "invented" or however became common AFTER the use of 2) and more or less at the same time of 3) above.

All the mentioned floppies had some physical characteristics in common:
a. they were round and spinned
b. they had two "sides"

Initially only one side of the disk was used, later by adding a magnetic head on the underside, both sides could be used.

The first sector of a floppy is the bootsector.

Then the idea of the hard disk came out, basically by putting on the same spinning axe a number of disks (and having two heads, one for the upperside and one in the underside of each disk) you had a larger capacity, closing this assembly in a protecting case, never to be opened by the user and protected from dust allowed an increased rotational speed and a "tighter" density of the magnetic media.

The filesystem in use at the time (at least for MS-DOS) was FAT12 (hex code 01) that has an addressing capacity of about 16 Mb.
To understand what I am talking about, my first hard disk had a capacity of 5 Mb. :huh:

So, theoretically one could access in the same way as the "old" floppy media any hard disk up to 16 Mb.

But it was evident that the increased speed (both in seek time and transfer time) of hard disks, their solidity, and the evolution in manufacturing magnetic media would have soon made the hard disk capacity increase dramatically and it's use become popular.

So they had a filesystem that "topped" at 16 Mb, and hard disks increasing in size.

What was the solution?

Two of them:
1) introduce a new filesystem "topping" at around 32 Mb (FAT 16 hex code 04)
2) introduce the concept of "partition", i.e. the ability of dividing a (big) disk into two or more parts, each one behaving exactly as the "floppy" disk

This latter idea was practically implemented by putting at the beginning of the media some additional sectors and "shifting" the beginning of the first partition a little bit (what are called commonly the "hidden sectors").

Basically, BEFORE the "usual" filesystem, an address table where the system would have looked up to find the beginning of the first "floppy disk" or partition, the MBR or Master Boot Record, containing the "partition table".

The first sector of a hard disk is a MBR.

The first sector of a partition is a bootsector, exactly like the "floppy" we have seen before, a partition on hard disk is essentially a "super-floppy".

In other words:
- ANY DEVICE that has as first sector a MBR (and thus a partition table) is a partitioned device or "hard disk like" device
- ANY DEVICE that has as first sector a bootsector is a non-partitioned device i.e. a "floppy" or "floppy like" or a "super-floppy", and the term "partition" or "super-floppy" can be used as synonyms when used as a comparative with "HD like" or "partitioned"

Read this:
http://www.ranish.com/part/primer.htm

Then, once got the basics, start reading from here:
http://www.pcguide.com/ref/hdd/

About history, sizes, geometries, barriers (both derived from BIOS and from filesystems).

I sometimes feel like a small child back in a classroom looking a blackboard with complex information & equations written thereon, starring in amazement & wonder, then looking around at my piers & wonder what level or understanding they have are they like me confused, or is it that I am in the wrong class?


Once done the homework :), come back here with the questions that you may still have. :)

:)

jaclaz

#3 MedEvil

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Posted 09 September 2008 - 04:42 PM

The filesystem in use at the time (at least for MS-DOS) was FAT12 (hex code 01) that has an addressing capacity of about 16 Mb.

What was the solution?

Two of them:
1) introduce a new filesystem "topping" at around 32 Mb (FAT 16 hex code 04)

Ehm jaclaz, would you please recalculate. Your young apprentice might believe you.

:huh:

#4 was_jaclaz

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Posted 09 September 2008 - 06:29 PM

Ehm jaclaz, would you please recalculate. Your young apprentice might believe you.

:huh:


Sure, as soon as you will provide some background to your request, I am not sure what the point is. :huh:

There are two kinds of FAT 16 partitions, the hex code 04:

http://thestarman.pc...m/mbr/FDISK.htm

A Brief History of Major Changes in the FDISK Program

MS-DOS 3.3 - Although partitions still had a maximum capacity of 32MB, this version was the first to introduce Extended DOS partitions* (a maximum of 24 partitions using the drive letters C: through Z:). But, only two physical drives were supported at that time.


Partition Type	Capacity ranges from	FAT type

  --------------	--------------------	--------

		01			  0  through 15 MB	 12-bit

		04		   16 MB through 32 MB	 16-bit

		05		   Extended Partitions	   N/A

and the nowadays more common FAT 16 hex code 06:

MS-DOS 4.0 - Partition sizes increased to a maximum capacity of 2.1 GB, but full use of these partitions required the MS-DOS program Share.exe to be loaded first. A new partition type (06) was added for partition sizes over 32 MB.

Partition Type	Capacity ranges from	FAT type

  --------------	--------------------	--------

		06		  32 MB through 2.1 GB	 16-bit

I seem not to be able to see where the supposed mis-calculation may have occurred.

jaclaz

#5 ispy

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Posted 09 September 2008 - 07:03 PM

Hi folks :huh: ,

@Jaclaz - First off many thanks for the informative reply, I am now knee deep in cylinders, heads, sectors, Axel grease & turbo chargers, Oop's sorry that's the car mechanics section, getting my wires crossed!
@ MedEvil

Your young apprentice might believe you

I'm tempted here to remain quiet but I'm afraid not young heading towards senior citizenship, retirement & a free bus pass!
Luckily all my teeth are my own just a about, but gravity, the old 9.81Metres per sec has made everything go southwards without going into too much detail of course :huh:

As they say you are never to old to learn!

R&R,

ispy :)

#6 was_jaclaz

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Posted 09 September 2008 - 07:26 PM

Besides, here on boot-land the term "padawan" is generally preferred over "apprentice:
http://www.boot-land...topic=1000&st=7
:huh:
but however the "young" is not to be intended as a reference to actual age, but rather to the time one has spent into training and trying mastering the Force Boot.

:huh:

jaclaz

#7 ispy

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Posted 09 September 2008 - 10:10 PM

@ Jaclaz, :huh:

So I would be called "O'L Crusty1" & you would be Master Jackal

One quick summary correct if I'm wrong,

The knee bone connected to the thigh bone.....

Sorry! "Super floppies" (although they are not floppy in construction) are anything that does not have a master boot record (Boot sector therein) but do have a boot sector, excluding Flash sticks & perhaps maybe the new solid state drives (Samsung no moving bits Giant flash sticks maybe). So in terms of disk construction the platters of a hard drive are the same in constructional makeup as say a double sided CD/DVD complete with sectors tracks etc albeit as you say hard drives are enclosed within a dust free environment and have actuators reading both sides of the disk or platter in the case of a HDD.

1 question do these actuators move across each independent platter surface all together in symmetry (vertically above each other to maintain what are called cylinders or are they capable of free independant movement, read different parts of the disk at the same time?

So its the boot sector where all the info is stored in respect Virtual non-standard Floppy images?

I'll stop there cuz I need to read more, good stuff all the same!

R&R,

ispy :huh:

#8 MedEvil

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Posted 10 September 2008 - 12:06 AM

Jaclaz you were talking in your post about filesystems. The link you provided talks about partition types.
A partition type 4 is only allowed to be between 16-32MB, but that has nothing to do with FAT16 filesystem limitations.
A FAT12 can address 4096 'units'
A FAT16 can address 65536 'units'
A FAT32(which is in reality a FAT28) can address 268435456 'units'

btw. the 2.1 GB Limit for Fat16 was also 'just picked' by M$, there are some OS which can use FAT16 up to 4GB.

:huh:

#9 was_jaclaz

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Posted 10 September 2008 - 08:18 AM

@Medevil
I still cannot see the problem in what I wrote, I was talking about DOS and the FAT 16 filesystem type 04 at the time was limited as reported.
When using first releases of MS-DOS a FAT 16 partition of type 06 would have been NOT recognized by the OS, the only one being 01 and 04.

I never said that it was an addressing limit of the FAT 16, the problem was due to the size of the clusters (or units as you call them), and no calculations were produced, hence I cannot see where something non existing may have been wrongly represented.

However, I guess that now it is clearer. :huh:

As well, the 4 Gb FAT16 hex code 06 was originally limited to 2.1 gigabyte because of the size of the clusters.
Using 64 kb clusters (to reach the aroung 4 Gb size limit) is a clear "abuse" of the FAT architecture.
Personally I never use FAT 16 partitions sized more then 995 Mb, as going beyond the 1st Gb already switches to 32 Kb clusters, that already create an "insane" amount of wasted space, let alone using 64kb one.

@ispy
No, sorry but you still miss a point, ANY DEVICE that is addressable in sectors (including Flash sticks and solid state drives) will have a first sector.
If the content of that sector is a MBR, the device is "HD like".
If the content of that sector is a bootsectorm the device is "floppy like".
This applies as well to virtual drives, if the first accessible sector of the image file is a MBR it is "HD like", if it is a bootsector it is a "floppy like" one.

1 question do these actuators move across each independent platter surface all together in symmetry (vertically above each other to maintain what are called cylinders or are they capable of free independant movement, read different parts of the disk at the same time?

Yes, there is just one arm that may bear more than one couple of heads, all heads of all platters move together and are always on the same "vertical" axe. (if you put the drive standing it will be "horizontal" :huh:)
Please remember that we are now talking about "old" hard disks, that did have several platters, some more recent disks only have one or two of them.

So its the boot sector where all the info is stored in respect Virtual non-standard Floppy images?

I am not sure that I get correctly the question, there is no difference between a virtual and a "real" device.
Standard or not standard, every BIOS in the world will access the first sector of a boot device, as well as any OS, and further actions will be carried depending on the contents of that first sector.

jaclaz

#10 MedEvil

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Posted 10 September 2008 - 01:51 PM

I still cannot see the problem in what I wrote, I was talking about DOS and the FAT 16 filesystem type 04 at the time was limited as reported.

And here you do it again. There exists no FAT16 type 04!!! There is only a Partition type 04, formated with FAT16! Big difference!

And to clear the part with the recalculation up. The values you gave are of course correct for the partition types, but you've wrote that they were filesystem (FAT) restriction and a 16Bit FAT just being able to address twice as much HDD space as a 12 bit FAT, simply can not be right. :huh:

The filesystem in use at the time (at least for MS-DOS) was FAT12 (hex code 01) that has an addressing capacity of about 16 Mb.

What was the solution?

Two of them:
1) introduce a new filesystem "topping" at around 32 Mb (FAT 16 hex code 04)


:huh:

#11 was_jaclaz

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Posted 10 September 2008 - 06:27 PM

Whatever you say. :huh:

In my book, and in the context I was talking about, a partition type existed that used a filesystem (hex code 04) using 16 bit addressing that was limited to 32 Mb in size.

What I was trying to convey was that there was no way at the time to let MS-DOS access anything bigger than 32 Mb, hence the need to partition the drive, dividing it in parts.

http://en.wikipedia....e#Initial_FAT16

Initial FAT16
In 1984 IBM released the PC AT, which featured a 20 MB hard disk. Microsoft introduced MS-DOS 3.0 in parallel. Cluster addresses were increased to 16-bit, allowing for up to 65,517 clusters per volume, and consequently much greater file system sizes. However, the maximum possible number of sectors and the maximum (partition, rather than disk) size of 32 MB did not change. Therefore, although technically already "FAT16", this format was not what today is commonly understood as FAT16. A 20 MB hard disk formatted under MS-DOS 3.0 was not accessible by the older MS-DOS 2.0. Of course, MS-DOS 3.0 could still access MS-DOS 2.0 style 8 KB cluster partitions.

MS-DOS 3.0 also introduced support for high-density 1.2 MB 5.25" diskettes, which notably had 15 sectors per track, hence more space for FAT. This probably prompted a dubious optimization of the cluster size, which went down from 2 sectors to just 1. The net effect was that high density diskettes were significantly slower than older double density ones.[dubious – discuss]


As well, according to my sources, the limit is attributed to the way the "initial" FAT16 was implemented:
http://www.pcguide.c...d/bios/size.htm

DOS 3 (32 MiB / 33.6 MB) Barrier: To get around the 16 MiB barrier, DOS 3.x was altered when the IBM PC/AT was introduced with larger drives. The first support for the FAT16 file system was added. However, a new barrier was introduced by the rather limited way in which FAT16 was originally implemented: cluster size was set to 2,048 bytes, and only 16,384 FAT entries were allowed, fixing maximum capacity at around 32 MiB. The ability to have multiple partitions was introduced at around the same time, but each partition could only be 32 MiB or less.


You are right in saying that the theoretical addressing limit of FAT16 is around 65536, actually 65517 but the limit was the above.

In other words, the "initial" FAT16 was implemented in a different way from the "normal" FAT16 (type 06) we are familiar with.

jaclaz




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