Difference between revisions of "3½" & 5¼" Disk Drives"

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These Floppy Disc Drives are not the original Amstrad standard.
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3½" & 5¼" Floppy Disc Drives are not the Amstrad standard yet the media and drives were far cheaper so they were common especially when used as a 2nd drive.
  
Yet they were far cheaper and are nowadays easier to use.
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During the lifetime of the CPC both drives were advertised in UK magazines with the 3½" becoming much more common in it's later years due to it's use in the PC. In Germany 5¼" were advertised and well supported by Vortex for much longer. Magazines also promoted the use of these drives especially with the use of another DOS or C/PM to be able to use their full capacity.
  
Especially the 3½" as these disk are still available in some retailers. You can also easily find such drives in any garbage if you properly scavenge old rusty computers.
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Both 3½" & 5¼" drives were often double sided and supported double density and high density although the Amstrad could only support Double Density.
  
These Disks couldn't be side switched manually.
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Nowadays the 5¼" drives are hard to find and are expensive, media is not made anymore and new-old-stock media is also hard to find. The 3½" drives can be found from old PC computers and there is still a read supply of new-old-stock media.  
The older models used only one side (360 KB)
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Double side (DD) or even High Density were available.
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Increasingly however it is often easier to use a disc drive emulator or one of the devices that can run games from SD cards.
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==Comparison of media costs==
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 +
3" disc (each) - £3.99
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3.5" disc (each) - 50p
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5.25" disc (each) - 50p
 +
 
 +
==Usage of Media==
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To make full use of the capacity of the media you need to use another DOS or C/PM on your CPC which can support more tracks and two sides. Then you can use around 720KB per disc.
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Without another DOS you can still use some of the capacity:
 +
 
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* 3½" discs can't be turned like 3" discs therefore with [[AMSDOS|AMSDOS]] you can use a manual side switch to choose the sides giving 2 x 178KB per side. Without the side switch it's just 178KB. Using discs like this back in the day was still useful as the media was cheaper.
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* 5¼" discs can be turned over like a 3" and you can write both sides if you cut a write protect hole on the other side of each disc OR like the 3½" a manual side switch can be used.
  
 
[[image:3.5.jpg|200px|thumb|Internal 3.5" drive]]
 
[[image:3.5.jpg|200px|thumb|Internal 3.5" drive]]
 
[[image:5,25_cable.jpg|200px|thumb|advertisement for 5,25" drive cable for CPC in 1990]]
 
[[image:5,25_cable.jpg|200px|thumb|advertisement for 5,25" drive cable for CPC in 1990]]
  
==Formats ==
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==Scavenged 3½"==
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It is worth noting that 3½" scavenged from PCs will lack the drive selection and ready signal. Often these drives will need a modification to make them useable OR you can make sure the drive motor is always on.
  
3"1/2
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==Common PC Formats ==
  
*DD = 720KB
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3½":
*HD : 1,44 MB
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5"1/4
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*DD = 720KB
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*HD : 1,44 MB
  
*360KB
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5¼":
*1.2MB
+
  
 +
*DD = 360KB
 +
*HD = 1.2MB
  
 
== Beware : HD ==
 
== Beware : HD ==
  
Nowaday the most common 3"1/2 disk is HD. These can be found as used or new old stock on auction sites.
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Nowaday the most common " disk is HD. These can be found as used or new old stock on auction sites.
  
 
But our beloved CPC can't understand easily the concept of High Density Disk with 1,44MB available... so you have to cheat to use the media: just put some opaque duct-tape (scotch-tape, whatever...) on the HD Hole.
 
But our beloved CPC can't understand easily the concept of High Density Disk with 1,44MB available... so you have to cheat to use the media: just put some opaque duct-tape (scotch-tape, whatever...) on the HD Hole.
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Tada the drive will think DD media is used and now it's usable.
 
Tada the drive will think DD media is used and now it's usable.
  
PC users used to do the opposite : file a HD hole on DD disk...this worked well sometimes.
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PC users used to do the opposite : cut/drill a HD hole on DD disk...this worked well sometimes.
  
 
You can also modify your HD drive to behave as a DD one (but this would be permanent of course).. Check for appropriate jumpers on your drive!
 
You can also modify your HD drive to behave as a DD one (but this would be permanent of course).. Check for appropriate jumpers on your drive!

Latest revision as of 08:24, 7 August 2025

3½" & 5¼" Floppy Disc Drives are not the Amstrad standard yet the media and drives were far cheaper so they were common especially when used as a 2nd drive.

During the lifetime of the CPC both drives were advertised in UK magazines with the 3½" becoming much more common in it's later years due to it's use in the PC. In Germany 5¼" were advertised and well supported by Vortex for much longer. Magazines also promoted the use of these drives especially with the use of another DOS or C/PM to be able to use their full capacity.

Both 3½" & 5¼" drives were often double sided and supported double density and high density although the Amstrad could only support Double Density.

Nowadays the 5¼" drives are hard to find and are expensive, media is not made anymore and new-old-stock media is also hard to find. The 3½" drives can be found from old PC computers and there is still a read supply of new-old-stock media.

Increasingly however it is often easier to use a disc drive emulator or one of the devices that can run games from SD cards.

Comparison of media costs

3" disc (each) - £3.99 3.5" disc (each) - 50p 5.25" disc (each) - 50p

Usage of Media

To make full use of the capacity of the media you need to use another DOS or C/PM on your CPC which can support more tracks and two sides. Then you can use around 720KB per disc.

Without another DOS you can still use some of the capacity:

  • 3½" discs can't be turned like 3" discs therefore with AMSDOS you can use a manual side switch to choose the sides giving 2 x 178KB per side. Without the side switch it's just 178KB. Using discs like this back in the day was still useful as the media was cheaper.
  • 5¼" discs can be turned over like a 3" and you can write both sides if you cut a write protect hole on the other side of each disc OR like the 3½" a manual side switch can be used.
Internal 3.5" drive
advertisement for 5,25" drive cable for CPC in 1990

Scavenged 3½"

It is worth noting that 3½" scavenged from PCs will lack the drive selection and ready signal. Often these drives will need a modification to make them useable OR you can make sure the drive motor is always on.

Common PC Formats

3½":

  • DD = 720KB
  • HD : 1,44 MB

5¼":

  • DD = 360KB
  • HD = 1.2MB

Beware : HD

Nowaday the most common 3½" disk is HD. These can be found as used or new old stock on auction sites.

But our beloved CPC can't understand easily the concept of High Density Disk with 1,44MB available... so you have to cheat to use the media: just put some opaque duct-tape (scotch-tape, whatever...) on the HD Hole.

Tada the drive will think DD media is used and now it's usable.

PC users used to do the opposite : cut/drill a HD hole on DD disk...this worked well sometimes.

You can also modify your HD drive to behave as a DD one (but this would be permanent of course).. Check for appropriate jumpers on your drive!

A clever choice

A great advantage at the time (in the 80's) was to get access to CP/M sofware library, as most of those were on such Floppy Disks.

Also, those Floppy Disks were far cheaper than the exotic 3", but... few CPC users actually own such drives.

Mostly professionnal users...The common snotling Gamer couldn't even dream of this (nor even knew it possible)... until nowadays.

As the magnetic disk is bigger...well the format is bigger too. It is common to get 720KB disk (using the 2 sides, so 80 tracks)

Software's issues

Many Modern CPC users replace their old 3" with an external 3"1/2, often adding a Disk drive A-B / B-A switcher (allowing the use of an external disk Drive as if it were the internal one = Drive A) and/or a side switcher to allow the use of a 3"1/2 disk like a 3" disk... switching manually the sides as needed by good old 3" disk drives (yet a decent software can do it).

The side switcher and A-B drive's switchers are needed only if you use old software (using AMSDOS), as most of them couldn't really figure they were loaded from B drives, or had no such feature as double sided drives.

They were designed for good old 3" drive so the 720KB DD external 3"1/2 is not implemented.

But modern software designers can allow this fairly easily.


Orion Prime uses the Double side feature, enabling a simple 720KB disk with no manual side switches.

Rick Dangerous 128+ (1.1 add-on) seems to allow the game to be loaded from the B drive.


It is up to the CPC-scene to design their software to include those options, allowing more un-modded drives to be simply used as external B drives with no need to add extra buttons and cable assemblies on the Amstrad.

As modifying all the software library of the good old times seems impractical, yet modern era software have to use this.

Software released on 3.5" disk

  • Orion Prime - This pure awsomeness even uses a full DD disk's 80 tracks with more than 700KB of Data, but you have to have a proper DD disk drive, as some older models may lack this feature...

Software released on 5.25" disk

Non 3" CPC disk drives

  • any scavenged rusty junk may be good enough nowaday, if you have a 664 or 6128...

Guides

Guide on how to connect a 3.5
Guide on how to connect a 3.5" drive to a CPC6128/664 with photos

Amstrad Computer User magazine published a two-page guide on how to connect a 5.25" drive to a CPC 464: