Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: HopperJF on April 30, 2008, 11:30:56 PM
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I bought an external hard drive today, the internal 40Gb was simply too small for my music collection and everything else I was used to having on the Mac's 60Gb drive. I have kept the internal and got a cheap Western Digital Elements drive at 160Gb for £49, only it's er.... not 160Gb.
Unfortunately this is nothing new in the market, disk manufacturers have been rounding up capacities for many years.
Take the 1980s for example. The Double-Density floppy disk advertised having a whopping 720k storage at the time, but actually DOS systems could only access 713k of it. The Amiga was not whiter than white either, with its standard 880k disks only usually containing 837k of space.
The so-called 40Gb hard disk in my box is actually only 33, and today I discovered the 160Gb drive I just purchased is actually only 149Gb. This is ridiculous.
This isn't a few megabytes of difference, it is a whopping 11 gigabytes less than advertised. Enough for a fully configured OS install and a fat wad of applications and some MP3s thrown in. A lot of space.
Now if it was 159Gb then that would be understandable, marketing a "160Gb" drive makes more sense. It would also be understandable if they marketed my drive as having a "150Gb" capacity.
I think manufacturers need to be more honest and stop this before eventually we will be seeing 1Tb drives with only around 800Gb of actual storage space.
Being the modest honest guy I am, when people ask me the capacity of the drive, I will say 150Gb. It's a shame manufacturers can't apply the same honesty.
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Yes, I understand you. I've never noticed the real capacity of my new HDDs although I knew it's bit lower. But that much? Doesn't it depend on filesystem too? I am not an expert...
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Or else you should just realise how the manufactures calculate their GBs.
Manufaturer
160 GB = 160 x 1000 x 1000 x 1000
Computer system
(160 x 1000 x 1000 x 1000) / (1024 x 1024 x 1024) = 149 GB.
Now do the math, and you will know how much storage space you have from your future TB drive.
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Well without altering the filesystem on my new one, it shows as 149Gb, it uses the somewhat appropriately named "vfat" filesystem :lol:
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Welcome to the early 1990s ?
Seriously man...it's common knowledge that the decimal powers of ten are in use since then for storage...and the rest goes to formatting.
Although you did actually get 720kB on a floppy back in the day...7 was used for formatting.
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doctorq wrote:
Or else you should just realise how the manufactures calculate their GBs.
Manufaturer
160 GB = 160 x 1000 x 1000 x 1000
Computer system
(160 x 1000 x 1000 x 1000) / (1024 x 1024 x 1024) = 149 GB.
Now do the math, and you will know how much storage space you have from your future TB drive.
Nowhere near a full terrabyte.
I'm amazed no one has complained about this sort of thing in the past, on the lines of false-advertising or at least misleading the public into thinking they will have a full X amount of space when really they get significantly less.
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JKD wrote:
Welcome to the early 1990s ?
Seriously man...it's common knowledge that the decimal powers of ten are in use since then for storage...and the rest goes to formatting.
Although you did actually get 720kB on a floppy back in the day...7 was used for formatting.
It is common knowledge, but why? It is wrong and misleading IMO. Not everyone is as knowledgeable about computers as the people who use this forum, and it might seem like a small petty issue to some but in my opinion if Joe Public buys a hard drive marketed at a certain capacity, then they should be able to access that capacity.
If a chunk of it is used for other data then take that extra off the marketed capacity.
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Off topic issue but you were ripped off anyway...
I got a 320gb external IOMega drive for about £50 just after christmas...
But yeah, they allways do calculate the capacity wrongly, I thought it was common knowledge.
Only problem I have with the external HD is the speed, backing up over USB2.0 isn't really realistic... and I haven't found anything nearly as good as Time Machine for XP/Vista.
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If a chunk of it is used for other data then take that extra off the marketed capacity.
That'd be confusing...since it depends on operating system and file system.
Maybe an 'estimate of formatted capacity based on windows'...who knows? who cares? The cost per GB is insanely low even if you factor in the decimal vs. binary difference
My first Amiga HDD was 85MB and it cost hundreds of pounds..but I think they were decimal MB too ;)
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From wdc.com:
One gigabyte (GB) = one billion bytes.
One terabyte (TB) = one trillion bytes.
Total accessible capacity varies depending on operating environment.
This is nothing new.
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Not Really a Swindle....
Heres a explanation from wikipedia.
"Hard disk drive manufacturers specify disk capacity using the SI prefixes mega-, giga- and tera-, and their abbreviations M, G and T. Byte is typically abbreviated B.
Most operating-system tools report capacity using the same abbreviations but actually use binary prefixes. For instance, the prefix mega-, which normally means 10^6 (1,000,000), in the context of data storage can mean 2^20 (1,048,576), which is nearly 5% more. Similar usage has been applied to prefixes of greater magnitude. This results in a discrepancy between the disk manufacturer's stated capacity and the apparent capacity of the drive when examined through most operating-system tools. The difference becomes even more noticeable (7%) for a gigabyte. For example, Microsoft Windows reports disk capacity both in decimal-based units to 12 or more significant digits and with binary-based units to three significant digits. Thus a disk specified by a disk manufacturer as a 30 GB disk might have its capacity reported by Windows 2000 both as "30,065,098,568 bytes" and "28.0 GB". The disk manufacturer used the SI definition of "giga", 10^9 to arrive at 30 GB; however, because the utilities provided by Windows, Mac and some Linux distributions define a gigabyte as 1,073,741,824 bytes (2^30 bytes, often referred to as a gibibyte, or GiB), the operating system reports capacity of the disk drive as (only) 28.0 GB."
See Pyrre explanation...thats better than wikipedia....good one! :). I couldn't be bothered to do the math.
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:-D
This is because windows (or other OS for that matter) multiply by decimal and not by binary...
one kilo binary byte is 1024 or 2^10
This is basic for what most OS calculate disk size.
But they multiply by 1000 not by 1024 as they should.
so
if you multiply 1024 by 1024 yo get:
1048576 which is the exact amount of binary bytes in one megabyte.
However
if you multiply by 1000:
1024 x 1000 = 1024000
And that is one megabyte calculated by most OS
And again
Binary:
1048576 x 1024 = 1073741824 byte or 1GB
If you multiply this by the expected size of your disk you should get the number of the size of your disk.
But os calculate:
1024000 x 1000 = 1024000000 as 1GB
This is the reason why disks appears to be smaller than they really are. But on a binary level they are the size they should be... However. some of the disk size is occupied by the File Allocation Table and its backup...
EIDT:
(300GB disk = 1073741824 * 300 = well :-) 300GB in binary. my calculator wont go so far.
My 300 GB disk is only 293GB in windows explorer, and in disk manager it is only 279GB... and in the bios post screen it is 298GB)
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with its standard 880k disks only usually containing 837k of space.
I'm pretty sure I was able to squeeze more than that out of a disk using some of the updated file systems. But, there you go, really, (except for whether or not you think a kilobyte is 1024 or 1000 bytes) the file system needs some space, too.
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Right, with OFS you only had 488 bytes usable per block, resulting in 837k capacity for a DD floppy.
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DBAlex wrote:
Off topic issue but you were ripped off anyway...
I got a 320gb external IOMega drive for about £50 just after christmas...
But yeah, they allways do calculate the capacity wrongly, I thought it was common knowledge.
Only problem I have with the external HD is the speed, backing up over USB2.0 isn't really realistic... and I haven't found anything nearly as good as Time Machine for XP/Vista.
I know, but it was bought on impulse and out of Maplin and Currys Digital (which are probably the same company anyway) the Currys Digital WD one was cheaper (Maplin wanted £80 for the same capacity but a DRM one)
Sooner or later though, they are going to have to change aren't they, because the gap is getting increasingly bigger everytime, when it goes into hundreds of gigabytes surely its time to change the way the capacity is marketed
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lcd screen sizes are at least correct as they don't count the tube you don't use.
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The XBOX 360 drive is worse, they say 20GB but it's only 13GB. Very silly.
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Not Really a Swindle....
Heres a explanation from wikipedia.
"Hard disk drive manufacturers specify disk capacity using the SI prefixes mega-, giga- and tera-, and their abbreviations M, G and T. Byte is typically abbreviated B.
It Is a SWINDLE.
That wikipedia quote is deceptive and should be changed in my opinion. (And I bet is has been changed many many times)
It implies that Hard drive manufactures have been rightfully using the SI standard since the beginning. This is not the case, as only since around 2000 has the SI defined the use computer terms kM MB and GB as being 1000 not 1024.
There is a JEDEC standard that pre-dates this by many years that defines the 1024 usage.
All(?) Operating systems that use these storage devices use the 1024 bytes per kB standard. How is it OK for Harddrive manufactures (or ISPs) to use a different standard.
The SI standards body did us all a big disservice by setting this silly standard. The different named definitions (kiBi) should have been made to the decimal version not the binary.
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I'm sure if you read the fine print on any hard drive, they tell you what you are actually getting.
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All(?) Operating systems that use these storage devices use the 1024 bytes per kB standard.
Yes they do. but when calculating anything above 1KB OS's multiply by 1000 making 1GB 102400Bytes instead of 1047576Bytes.
The SI standards body did us all a big disservice by setting this silly standard. The different named definitions (kiBi) should have been made to the decimal version not the binary.
Well i disagree... the SI standards are made to differ in terms. KB is Kilo Byte and can be interped as 1000 Bytes. In SI standards it is totaly correct. However KiBiByte is Kilo Binary Byte and cannot be interped "the wrong way" it uses the binary number sequence. while KB can be using decimal number. And therefor not entirely correct...
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The best you could hope for by taking this to Trading Standards (or the equivalent depending on which country you live in) would be them forcing the manufacturers to specify that they had used a decimal rather than binary equation to calculate the capacity of the disk. But anybody who knows the difference will already know that hard disks are never formatted to the advertised capacity, and people who don't know the difference will still expect a 160GB drive, even if the packaging says "160GB (decimal)".
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moto
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Well i disagree... the SI standards are made to differ in terms. KB is Kilo Byte and can be interped as 1000 Bytes. In SI standards it is totaly correct. However KiBiByte is Kilo Binary Byte and cannot be interped "the wrong way" it uses the binary number sequence. while KB can be using decimal number. And therefor not entirely correct...
Well I can't argue that KiB is NOW unambiguous. However GB, MB, KB and kB are now as a result of SI, almost completely useless as they have set a standard that goes against decades of accepted usage. The only Computer related system previous to 2000 that didn't use exclusively use 1024 was magnetic media.
It would have been fine if they set two new terms instead of redefining an accepted computer and electronics standard (and a JEDEC standard).
eg: define KiB and KeB (i=bInary e= dEcial) or similar. That way there would be no ambiguity when the SI standard was taken up, unlike what we have now with kB.
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I have just bought a 320Gig HD to put inside my MBP... wow... Once formatted it's about 298gig... hello where did my 20gig go!!! Hehehe, I'm not actually bothered since Hard drives for what ever reason have always been measured in decimal bytes by manufacturers. I don't care since they are all sold like that... but what the hell... that's a lot of space inside a laptop!!! :-)
The problem we face now, is that if we wanted to move the more helpful Binary system, ALL manufacturers would have to do it together. Nothing would be worse or more confusing than manufacturers stating different capacities for the same size drive.
What we might see is a change with SSDs... since these are built using Chips and therefore inherently measured in powers of 2... we might expect to see a shift to binary sizes over decimal ones.
I notice that my old 540Mb HD in my A1200 is about the same size as my 512Mb Compact flash...
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At the end of the day I just hope that OSs don't start using the SI definitions as that would just wast more cycles to display the value. As a power of 2 divide is only a left shift away.
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Yes they do. but when calculating anything above 1KB OS's multiply by 1000 making 1GB 102400Bytes instead of 1047576Bytes.
Which OSs?
An example from my winXP system:
filename: AmigaTribute.mp4
size: 20.6 MB (21,604,082 bytes)
21,604,082 bytes / 1024
= 21098.7 kBytes
21098 / 1024 (NOT 1000)
= 20.6 MB
I know there are some examples in the computer area where 1024 bytes = kb then 1000 = MB, GB have been done but they are a small minority
It would take an OS many more cycles to calculate the 1024 1000 1000 version vs a 1024 1024 1024 system.
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Yes they do. but when calculating anything above 1KB OS's multiply by 1000 making 1GB 102400Bytes instead of 1047576Bytes.
Wrong.
Well i disagree... the SI standards are made to differ in terms. KB is Kilo Byte and can be interped as 1000 Bytes.
A kilobyte is 1024 bytes, regardless of any effort by marketing boards to redefine it.
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also...
if you format a drive to have 512byte blocks, you loose part of the 512bytes with header/pointer information. the smaller the block size, the more headers, the more diskspace lost. so a 2Kbyte block formated disk looses one quarter the disk space compaired to a 512byte block formatted disk. sounds great huh? but wait a minute. a file cannot be smaller than one disk block, and a block cannot contain more than one file. so a 512byte file saved to a 2Kbyte block, leads to 1.5Kbytes of empty (slack) space that can't be used by anything else.
also, if you have a few massive blocks, even if you have lost of disk space left, if all the blocks are used up, you won't be able to save anything to the drive.
most the time thats why "file size" and "size on disk" is different. size on disk takes into account all the 'slack' space used by incompletely filled blocks, plus the block headers.
so you have to weigh it all up.
if you have a disk that is going to have a few massive files on it, its best to use a large block size, as you get more disk space back, and the drive has less indexing work to do, meaning its a bit faster, especially in a serial read/write scenario (aka video recording/playback).
if you have lots of tiny files, you really want a small block size so you don't waste disk space with lots of 'slack' space.
i know with todays massive drives, its not so much the concern it once was when we were piddling about with drives in the tens to hundereds of megabytes. but it can make a difference with drive performance, and percieved capacity.
ok so you accept that your nice 1000GB drive is counted in decimal, so you plug it in and accept the 50GB+ loss in actual capcity, but you then loose another what, 9Gb in formating? yay!
sorry for the essay... bored... lol :lol:
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Taken from Seagate's FAQ's about their drives ... Western Digital say the same thing ...
Quote ... "Hard drive manufacturers market drives in terms of decimal (base 10) capacity. In decimal notation, one megabyte (MB) is equal to 1,000,000 bytes, and one Gigabyte (GB) is equal to 1,000,000,000 bytes.
Much of this information is available from the National Institute of Standards and Technology at http://physics.nist.gov/cuu/Units/binary.html
Programs such as FDISK, system BIOS, and Windows use the binary (base 2) numbering system. In the binary numbering system, one megabyte is equal to 1,048,576 bytes, and one gigabyte is equal to 1,073,741,824 bytes.
Simply put, decimal and binary translates to the same amount of storage capacity. Let's say you wanted to measure the distance from point A to point B. The distance from A to B is one kilometer or .621 miles. It is the same distance, but it is reported differently due to the measurement.
Capacity Calculation Formula
Decimal capacity / 1,048,576 = Binary MB capacity
Example:
A 40 GB hard drive is approximately 40,000,000,000 bytes (40 x 1,000,000,000).
40,000,000,000 / 1,048,576 = 38,162 megabytes" ... unquote
In other words, formatted capacity and actual capacity are two different things. They just round the figures up to make it look good in the adverts. :-D
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tokyoracer wrote:
The XBOX 360 drive is worse, they say 20GB but it's only 13GB. Very silly.
A lot of that is the XBox Operating System, I know I have one :-)
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@jorkany
Quote:
Yes they do. but when calculating anything above 1KB OS's multiply by 1000 making 1GB 102400Bytes instead of 1047576Bytes.
Wrong.
What is correct then?
Quote:
Well i disagree... the SI standards are made to differ in terms. KB is Kilo Byte and can be interped as 1000 Bytes.
A kilobyte is 1024 bytes, regardless of any effort by marketing boards to redefine it.
Oh really...
one byte is, one... one kilo is one thousand (1000).
1 byte multiplied by 1000 is still one thousand...
K=1000
B=Byte
there is nothing that say it IS calculated binary or decimal!
That is why KiB or KibiB (kilo binary byte) were invented...
It confused some people...
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"I have just bought a 320Gig HD to put inside my MBP..."
i was thinking of getting one of them mbp's till i saw the price. when did you buy? how much did you pay? :-o
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@ monami
MBP?
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MacBook Pro.
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moto
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HopperJF wrote:
The Amiga was not whiter than white either, with its standard 880k disks only usually containing 837k of space.
Actually, the Amiga could access 879KB with FFS. 837 was the capacity with OFS. Bear in mind also that those floppy disks actually have a capacity of 1MB, and HD floppies have a 2MB capacity unformatted. PCs could use 720KB or 1.44MB of the HD types, Amigas could use 880Kb or 1.76MB. After that you have the overheads of disk.info files, volume information and other filesystem stuff taking up another KB or two...
Being the modest honest guy I am, when people ask me the capacity of the drive, I will say 150Gb. It's a shame manufacturers can't apply the same honesty.
I dunno, basically this has always been the case, it's only more obvious recently with massive disc capacity widening the gulf between base 2 and base 10, and in fairness I've always seen a remark printed on hard drive documentation to the effect of 1Gb=1,000,000,000 bytes. It's just a convention, the same way that the kW output of your car, measured at the engine, is much less by the time the power reaches the wheels due to losses in the transmission. Once it's quoted as flywheel power, it's really up to the consumer to know the difference. It's not nice, I agree, but I don't see the problem with manufacturers bending stats to sell products once they follow a convention that standardizes it.
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Daedalus wrote:
Actually, the Amiga could access 879KB with FFS. 837 was the capacity with OFS. Bear in mind also that those floppy disks actually have a capacity of 1MB, and HD floppies have a 2MB capacity unformatted. PCs could use 720KB or 1.44MB of the HD types, Amigas could use 880Kb or 1.76MB. After that you have the overheads of disk.info files, volume information and other filesystem stuff taking up another KB or two...
You are indeed correct, it has been such a long time now that I used an Amiga properly yet Amiga.org is one of my most visited websites :crazy:
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I remember formatting the amiga disks in a special matter it would give capacity of 1MB...
I don't remember what i used to format the disks in that matter though....
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"Creative Sued for Base-10 Capacities On HDD MP3 Players"
http://hardware.slashdot.org/article.pl?sid=08/05/02/0128239
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I remember formatting the amiga disks in a special matter it would give capacity of 1MB...
I don't remember what i used to format the disks in that matter though....
diskspare.device, upto 984 kB, is one contender.
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I just got my Externalt 160 GB HDD delivered today - My iMac says it only has 149 GB :-S ... Sooo... Good for me that I read this thread.
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zipper wrote:
I remember formatting the amiga disks in a special matter it would give capacity of 1MB...
I don't remember what i used to format the disks in that matter though....
diskspare.device, upto 984 kB, is one contender.
If you rewrote the trackdisk.device to use 8B/10B encoding instead of MFM... then you could proably incraese a standard floppy capacity to 1.4Megs...
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Its all bit's and byte's
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The only reason to use binary kilos, megas ,... vs decimal ones is that it does make sense in some areas: chips (RAM, ROM) are rectangular in shape and their column and row sizes are powers of 2, so total size (=area) is also a power of 2 - using 1024 based prefixes makes sense since a chip is exactly e.g. 16 M(i)b in size.
In other contexts those odd prefixes make no sense at all (telecommunications, mass storage) as all sizes/speeds are arbitrary and have no 'natural' boundaries. Here you should definitely use decimal SI prefixes. All those arguing against this should think a moment about what makes more sense to use as standard - a 'traditional' feeling shouldn't be the only reason.
Just my .02.
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bottom line:
Everybody, except for hard drive manufacturers, use base 2 to indicate capacity.
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base2 is used for memory since that is the way that the memory is actually addressed.
decimal is used for the hard drives because (with chs or lba, etc.) that is how bytes are actually addressed on the disk.
what the os actually does with the disk and allows for free space is beyond the control of the drive producer. the best they can do is give the full unformatted capacity.
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koaftder wrote:
Everybody, except for hard drive manufacturers, use base 2 to indicate capacity.
No - everybody, except for memory manufacturers, uses base 10 to indicate capacity.
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Zac67 wrote:
koaftder wrote:
Everybody, except for hard drive manufacturers, use base 2 to indicate capacity.
No - everybody, except for memory manfacturers, uses base 10 to indicate capacity.
It does make sense, though, to use base 2 to measure the capacity of a binary data storage medium... think you not?
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flash drives, cdroms, blah blah. Every storage uses base 2 except for hd mfgr.
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Well, it's digital, but its addressing is nothing on any binary basis. Rather, the size of a mass storage device depends solely on manufacturing, engineering and marketing decisions, thus entirely arbitrary.
Actually, I was of the binary fraction some years ago, but as soon as you work with stuff not entirely computer related, you start thinking about the traditional 1024 units - and find there's very little reason for them.
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Zac67 wrote:
Well, it's digital, but its addressing is nothing on any binary basis. Rather, the size of a mass storage device depends solely on manufacturing, engineering and marketing decisions, thus entirely arbitrary.
Actually, I was of the binary fraction some years ago, but as soon as you work with stuff not entirely computer related, you start thinking about the traditional 1024 units - and find there's very little reason for them.
Well as a factor 1024 is rather useful for quickly scaling on a binary computer since it only requires a shift.
But the basic unit of data is the (8bit) byte, which maybe an unfortunate accident of history... but it does mean that the conventions put it place to conveniently use that unit are here to stay...
As some who probably speaks German fluently, I would expect you to accept the use of seemingly arbitrary conventions that exist for no other reason than historic :-)
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:lol: - granted.
I've come to somewhat dislike the binary units (or rather the grey zone between the binary and the decimal kilos) and have decided to stick with the SI compatible 1000 where more logical - obviously it's still your own choice today, but imho you shouldn't object to people using the slightly more modern version when it seems fit (and makes your products look larger).
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Zac67 wrote:
:lol: - granted.
Du glaubst mir, ich bin sehr neidisch... (oder vielleicht, Du musst mir glauben, ich bin sehr neidisch. ) For some odd reason I keep forgetting in inflect masculine nouns in the accusative case at the moment... it's very frustrating, as I notice the mistake as soon as I make it... And so do all my German friends :getmad:
I've come to somewhat dislike the binary units (or rather the grey zone between the binary and the decimal kilos) and have decided to stick with the SI compatible 1000 where more logical - obviously it's still your own choice today, but imho you shouldn't object to people using the slightly more modern version when it seems fit (and makes your products look larger).
Indeed, I don't have a problem either way... Just as long as I know which is used :-)
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bloodline wrote:
Du glaubst mir, ich bin sehr neidisch... For some odd reason I keep forgetting in inflect masculine nouns in the accusative case at the moment... it's very frustrating, as I notice the mistake as soon as I make it... And so do all my German friends :getmad:
I feel great respect for those taking on this illogical and (at times) cumbersome language - and you're doing quite well. Don't get frustrated, the best way to learn a language is by using it. ;-)
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Zac67 wrote:
bloodline wrote:
Du glaubst mir, ich bin sehr neidisch... For some odd reason I keep forgetting in inflect masculine nouns in the accusative case at the moment... it's very frustrating, as I notice the mistake as soon as I make it... And so do all my German friends :getmad:
I feel great respect for those taking on this illogical and (at times) cumbersome language - and you're doing quite well. Don't get frustrated, the best way to learn a language is by using it. ;-)
Danke, das ist sehr nett von dir! Ich versuche, es ist spaß, aber ziemlich schwer... Und ich bin jetzt betrunken :-)
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http://www.afterdawn.com/news/archive/13830.cfm
interesting...
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Hard drive claimed capacities are and always have been a con, the manufacturers want people to think they are buying more storage space than they are actually getting.
Instead of legitimising the practice, it should have been stopped, and HD manufacturers made to use the binary measurement.
There is nothing to stop memory manufacturers from using decimal capacity measurements on their products now, so long as the state on their packaging that 1MB = 1000000 bytes. Addressing difficulties will be other peoples problems, most easily solved by having a non-contiguous memory architecture with gaps between each block of memory, not the memory manufacturers problem.
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It'd not only be illogical but also uneconomical to build RAMs in non-power-of-2 sizes. Wikipedia: RAM/Operation Principle (http://en.wikipedia.org/wiki/Dynamic_random_access_memory#Operation_principle)
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bloodline wrote:
zipper wrote:
I remember formatting the amiga disks in a special matter it would give capacity of 1MB...
I don't remember what i used to format the disks in that matter though....
diskspare.device, upto 984 kB, is one contender.
If you rewrote the trackdisk.device to use 8B/10B encoding instead of MFM... then you could proably incraese a standard floppy capacity to 1.4Megs...
I once (in 1998) wrote a "tbc.device" which used "three bit encoding" for two data bits instead of MFM (two encoded bits for one data bits) and theoretically allowed 16 blocks per track. Using 82 cylinders, you could reach 1312 KB per DD disk. Unfortunately, I only managed to get the encoding stable for the first 40 cylinders -- probably due to precompensation after this mark, the reading of the data was not stable. I gave up the project as floppies were becoming more and more obsolete at that time anyway.
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Believe it or not it was as recently as 1997 that the most blank floppy disks were sold, the following year being overtaken by CD-Rs
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platon42 wrote:
bloodline wrote:
zipper wrote:
I remember formatting the amiga disks in a special matter it would give capacity of 1MB...
I don't remember what i used to format the disks in that matter though....
diskspare.device, upto 984 kB, is one contender.
If you rewrote the trackdisk.device to use 8B/10B encoding instead of MFM... then you could proably incraese a standard floppy capacity to 1.4Megs...
I once (in 1998) wrote a "tbc.device" which used "three bit encoding" for two data bits instead of MFM (two encoded bits for one data bits) and theoretically allowed 16 blocks per track. Using 82 cylinders, you could reach 1312 KB per DD disk.
Oh, that sounds cool... imagine if you had released that in 1990 :-)
Unfortunately, I only managed to get the encoding stable for the first 40 cylinders -- probably due to precompensation after this mark, the reading of the data was not stable. I gave up the project as floppies were becoming more and more obsolete at that time anyway.
Would precompensation really affect this? I would suggest that perhaps it was more likely that you might have made a calculation error that only showed up when the numbers got big enough. Not wishing to cast aspersions upon your code or abilities :-)
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HopperJF wrote:
Believe it or not it was as recently as 1997 that the most blank floppy disks were sold, the following year being overtaken by CD-Rs
Sounds about right... I was still buying floppies up to 2000... though not after... now I don't have a modern computer with a floppy drive... (/me leers at his old Althon64 3200 in the corner :-D).
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HopperJF wrote:
Believe it or not it was as recently as 1997 that the most blank floppy disks were sold, the following year being overtaken by CD-Rs
I can absolutely and totally believe it! I left Australia at the end of 1997, and remember well the aftermath of Windows 95 - a LOT of folks I knew were really unhappy with it right after it's release (for reasons I don't know - I was still using my Ami and didn't really care that much). But there was the hype of Windows 98 on the horizon, and not many folks couldn't afford CD-RW tech at that time for backups - I knew a lot of folks that were bulk buying floppies 'just in case'
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bloodline wrote:
Unfortunately, I only managed to get the encoding stable for the first 40 cylinders -- probably due to precompensation after this mark, the reading of the data was not stable. I gave up the project as floppies were becoming more and more obsolete at that time anyway.
Would precompensation really affect this? I would suggest that perhaps it was more likely that you might have made a calculation error that only showed up when the numbers got big enough. Not wishing to cast aspersions upon your code or abilities :-)
Well, the errors occurred exactly on the edge to cylinder 40 and *all* tracks after that were bad. AFAIK the floppy controller uses two or four different "zones" with different precompensation, switching at exactly half through the disk. I'm pretty sure it was no calculation error (and 40/80 is not even a power of 2, nor a big number).
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I understand you used no write precompensation at all? Then that's probably the cause. Local velocity of the medium increases constantly inward - on track 40 you have a ~35% higher speed, rising to nearly double speed on track 80. I'd guess even three different precomp zones would be necessary. Nice project though. ;-)
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Zac67 wrote:
I understand you used no write precompensation at all? Then that's probably the cause. Local velocity of the medium increases constantly inward - on track 40 you have a ~35% higher speed, rising to nearly double speed on track 80. I'd guess even three different precomp zones would be necessary. Nice project though. ;-)
Ahhh, right! I assumed that either Paula or the drive electronics itself would have handled the Precompensation... but Paula is very simple... so I guess everything has to be done in software... Makes you glad that Floppies have gone really! :-)
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I still use floppies fairly often, although that is no secret really :lol:
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i'm glad to see floppies go. i bought 2 new boxes of 40 from argos a few years ago. 2 different makes. and lots started to show bad sectors after a few uses. i had to keep them as i developed a problem where i couldn't return faulty goods! (part of my ocd.) i didn't see how it was possible for them to be faulty brand new and out of the box. odd.
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Zac67 wrote:
I understand you used no write precompensation at all? Then that's probably the cause. Local velocity of the medium increases constantly inward - on track 40 you have a ~35% higher speed, rising to nearly double speed on track 80. I'd guess even three different precomp zones would be necessary. Nice project though. ;-)
I used the trackdisk.device RAW (MFM) writing routines to avoid having to hack paula registers directly, so they should cater for precomp automatically... but who knows why it failed. It was a nice experience getting that low level :)