Why Amstrad chose the 3" drives

[eto]

In a discussion on Facebook, Roland Perry made a comment, where he explained why Amstrad chose the 3" drives over 3.5". Information that was already available, but afaik not yet in one single comment meant specifically to stop the rumours around it:

"...if only I could find a way to stop people spreading false rumours about the reason we chose 3" floppies"
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"One of the features was you could safely stick the media in your shirt pocket - even put on a stamp and mail it. But the main reason was because the format was IBM-5.25" compatible (so we could use existing controller chips and driver software) as well as being electrically compatible.

Although the drives we shipped in production needed a trivial-to-make adapter lead for attaching to a PC (whereas the originals had the exact same edge connector).
You may have noticed that as well as the native formats (which had slightly higher capacity) we also supported "IBM format", which was what a software developer who put a 3"
drive on his PC would have had in his hand without any tweaks at all to that PC (typically running CP/M-86).
3.5" drives were wierd and wonderful back then, and it was couple of years before IBM annointed them by shipping in one of their own PCs."




"We also made the decision early enough in the project that prototype DDI-1's were used to load the demonstration software at the original 464 press launch. The format then rolled over to the PCW (as well as the 664/6128)."

[TotO]

Of course, its answer is obvious and anyone interested in computers should knows that. Only people who don't know anything about it and think with prejudices can ask themselves these kinds of questions.

I'll be rather curious to know if the GateArray (prototype) was at one point able to handle a 6-bit (64 colours) palette before being cleverely reduced to 27 colours, perhaps for reasons of room or pin count of the final package.

[eto]

and some more from another thread




First, a few dates: The 464 launch (where we had a protoype DDI-1 to load the games) was in April 1984, and the decision to use 3" drives would have been taken several months earlier.

The IBM Convertible, the first machine of theirs to embrace 3.5" drives April 1986, and the PS/2 April 1987.

The Amiga was July 1985, and while the Mac was a 1984 design, the machine was in a completely different market, and ten times the price of a 464.

A few other designs with 3.5" were around, but the Sony drives used were quirky (rotating at different speeds on different tracks, and using GCR rather than MFM coding) as well as extremely expensive.

It was important for us that we could use existing floppy disc controller chips, and as a bonus all you needed was a simple cable converter to plug a classic 5.25" drive onto a CPC, and thus transfer sofware which had been developed on an IBM PC, or similar. (Alternatively, one could add a 3"drive onto the IBM PC).

Having picked the form factor for the DDI-1, it was clearly the best to use for the CPC664 (which is simply 464 and DDI-1 in a single enclosure), the 6128, and the PCW series which was designed starting in mid 1984.

In order to deliver all these machines at the prices we did, it was necessary (for Matsushita) to set up a dedicated production line for the floppy drives, which were also slimmer than the mythical "warehouse full of bankrupt stock".

I did see a few Hitachi 3" drives, but they were constructed with a fatter cast aluminium chassis, echoing a classic 5.25" design, and an edge connector rather than pins.

There's a picture of one here, although it's untrue they (rather than the 3" format) were used by Amstrad!

https://www.worthpoint.com/worthopedia/hitachi-floppy-disk-drive-amstrad-pcw-166829335

[ComSoft6128]

Thanks for the info, I don't use Social media so its nice when this type of thing is brought to the Wiki

[TotO]

Matsushita aka Panasonic is one of the electronic leader in Japan and they have produced high quality floppy disc too. The Amsoft label came from the rebranded design of them for the Amstrad CPC and PCW market.

[Gryzor]

Lovely, thanks for sharing from FB!

[Sykobee (Briggsy)]

Good questions and answers there. The 'scrapheap' rumours were very pervasive.

Good solid disks, and the cases with inlays were very useful, although they soon disappeared with the 10-packs.


The double sided, double density designs of the 3.5" drives soon after were the death knell for the 3" format, which took longer to get DSDD drives, and in fewer machines (PCW 8512 I think had one?)


For the lifetime of the CPC the capacity wasn't a big issue, some later games needed two sides (Times of Lore comes to mind) but even then I bet some simple compression would have worked wonders.