There was a time when floppy disk drives were big, expensive devices that in many cases, instead of being components of a computer, would be separate machines connected by a cable, in some cases with their own CPU. A well-known example was the Commodore 1541, which had a similar CPU to the Commodore 64.

I personally only ever had one external drive, but when you look at photographs of setups with two drives (very desirable if you could afford it), they are always side-by-side, taking up an awful lot of desk space. Even the CBM 4040 dual drive, places the drives side-by-side in a single very wide case.

It seems to me that since disk drives are fundamentally horizontal devices that want to be wide rather than tall, the obvious solution would be to stack them vertically. Maybe this would result in each drive picking up heat and vibration from the other one, but if this was tolerable when they were stacked vertically in a PC tower case, why not for external drives?

Were external disk drives ever stacked vertically? If not, why not?

  • 2
    Since there is no reason to prefer any orientation, this question asks for opinions about design, thus not realy OT at all.
    – Raffzahn
    Apr 4, 2019 at 15:35
  • 3
    @Raffzahn and here we agree ;) Any orientation is allowed on floppies except upside-down...
    – tofro
    Apr 4, 2019 at 16:33
  • 4
    @tofro, "Any orientation is allowed on floppies except upside-down" - And here, I will disagree, as upside-down is certainly a valid orientation for floppies. In fact, back in the day, I cut notches into quite a number of floppies so I could put them in upside-down and double my storage capacity.
    – Glen Yates
    Apr 4, 2019 at 21:03
  • 3
    @GlenYates I guess you turned the disk upside down and not the drive?
    – tofro
    Apr 5, 2019 at 8:57
  • 3
    @Xen2050 Mechanically, I'd guess they'd work fine - It's more about dust protection that dust may fall where designers didn't think of. In 3 1/2" drives the springs that press the disk upwards when ejecting are designed to work against gravity, not with it
    – tofro
    Apr 6, 2019 at 7:32

9 Answers 9


It seems to me that since disk drives are fundamentally horizontal devices that want to be wide rather than tall,

To me they are taller than wide. After all, that's as well the orientation IBM did put the very first drive, so anything else is plain wrong, isn't it :))

the obvious solution would be to stack them vertically.

That's pure opinion and up to the designer how he imagines a drive to look best or fit best. The drives itself work in any orientation with any angle equally well.

It seems to me that since disk drives are fundamentally horizontal devices

As said before, they are not, they work in any orientation. At least as long as we talk about the technology. If at all, any orientation can come from ball bearing involved. Except, for simple low speed application next to any standard bearing will offer the needed support strength - if that drive has one at all.

Were external disk drives ever stacked vertically?

It has been used in any combination you may think of.

  • Horizontal side by side like in a DEC RX01/02 - as that will need less HE in a rack

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  • Horizontal above each other like the Atari 815

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  • Vertical side by side like IBM's 6360 8" drive

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  • Vertical above each other in an Amstrad PCW8512 ('borrowed' from Chromatix' answer - to finally fill this slot)

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  • Or even both like with a Heathkit H17 case where two dives were mounted horizontal side by side, but when a third drive got added they where turned vertical to fit the case.

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  • Heck, they where even Computers mouting them both way at the same time:

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  • And then there was the DEC RX-50 dual drive, used in PCs to be placed either as desktop (with the drive horizontal) or tower (now vertical), whatever fits the desk.

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  • 2
    I'm disappointed to see that you've not included any examples of them being oriented vertically and then stacked on top of each other
    – Valorum
    Apr 4, 2019 at 22:54
  • 5
    @Valorum I'm so sorry, there is a DEC machine doing exactly this, but I couldn't find any worthwhile picture so far. Shame on me.
    – Raffzahn
    Apr 4, 2019 at 23:01
  • 6
    The Vobis one designed by Colani still makes me uncomfortable
    – Lars Beck
    Apr 5, 2019 at 7:27
  • 2
    @Valorum, Those last two computers (they look like Rainbow 100A to me); the ones pictured are fitted with a hard drive and a dual floppy, but could be fitted instead with two dual floppy drives (i.e. four floppy drives) stacked in the same configuration you mention. Apr 5, 2019 at 7:44
  • 3
    @Valorum This case albeit relatively modern, and for internal drives, has three drives, vertically orientated, mounted atop one another!
    – TripeHound
    Apr 5, 2019 at 12:37

Yes; this was standard procedure for at least the BBC Micro:

enter image description here

Including for third-party drives:

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Presumably because two drives arranged that way were only just taller than the machine itself:

enter image description here

  1. I don't think your claim that never happened is generally true
  2. It makes a lot of sense to put drives side by side when you want to place the drive set between computer and CRT (like many Apple users did). That wouldn't work well with stacks.
  3. Especially twin 3 1/2" drives were very often sold as vertical stacks. But some vendors also did the same with the larger drive sets
  4. If you look at earlier drives, 2 x 5 1/4 full-height drives stacked on top of the other really would be awkward to handle (but, see here) - that simply looks clunky.

Other than that, I don't see a technical reason why you wouldn't want to stack drives on top of the others. The frames of 5 1/4 drives are mostly aluminium castings, so stable enough to stack, and heat really shouldn't be a problem with floppy drives.

German Wikipedia seems to know how to stack Commodore 4040 drives as well. You simply need to have enough of them ;)

  • 1
    "Heat really shouldn't be a problem with floppy drives." That's true but the power supply generates heat. Apr 4, 2019 at 18:36
  • 1
    @traal but you won't stack the power supply?
    – tofro
    Apr 4, 2019 at 18:38
  • On the top or the bottom? Passive or active cooling? Apr 4, 2019 at 18:53
  • For Apple 's It was very common to have two drives stacked vertically and a CRT on top of the base unit May 1, 2021 at 21:39

One configuration I think Raffzahn missed so far was two independent drives stacked on top of each other. That was the recommended method for multiple Amstrad 3" drives: amstrad cpc464

(Image source: Gallery - Category: CPC464 - Image: CPC464 (b) setup - Roland in the caves)

  • 1
    Common for CBM PET drives I can remember having a stack 3 or 4 high of the various drives. Apr 22, 2019 at 0:16

Here's an Amstrad PCW8512, which featured two 3" hard-shelled floppy drives, both vertically oriented and vertically stacked, built into the side of the monitor. A very space-saving design.

enter image description here


In the TRS-80 Model I and Model II ecosystems, floppy drives normally had the disk oriented vertically. This made the drives "tall rather than wide", and placing multiple drives side-by-side worked well. enter image description here

In the Model III, two horizontal drives were stacked vertically in the main housing, to the right of the CRT (and above the numeric keypad).

Model III
(source: nightfallcrew.com)

  • 2
    While interesting, this is not really an answer to the question
    – tofro
    Apr 7, 2019 at 7:29

Since the question specifically references Commodore 8-bit drives, I thought I'd add a few details here.

The PET/CBM series dual drives used both configurations internally: While the 5.25" drives (like the 4040 in the question) were stacked horizontally

CBM 4040 / Source: https://de.wikipedia.org/wiki/Commodore_4040

the 8280 stacked two 8" drives vertically:

CBM 8280 / Source: http://www.6502.org/users/andre/petindex/drives/gallery/8280.gif

These units were, in turn, designed to be stacked vertically (and built like tanks to they could withstand each others weight):

Stack of CBM drives / Source: https://de.wikipedia.org/wiki/CBM-Diskettenlaufwerke

The only Commodore 8bit drives not designed to be stacked vertically were those in the 1541-style case (1540, 1541, 1551, 1570, SFD 1001). Here, Commodore put a transformer + linear regulator power supply (heavy, hot) into a comparatively small and not very sturdy case (see https://www.bayerischer-stenografenverband.de/fotos/2017_BM_Computermuseum.jpg for a side-by-side). Heat was a problem even without stacking (see e.g. http://cbmmuseum.kuto.de/floppy_vc1540.html). So the slight slant in the case top was probably intentional to discourage stacking.

Commodore solved the heat issue first in the 1571 (switch mode power supply), then in the 1541-II and the 1581 (external power supply). All those again have flat tops and are designed to be stacked.

This picture shows the slant of the 1541 (bottom) and the stackability of the others (1571, 1541-II, 1581, from bottom to top) quite nicely:

1581, 1541-II, 1571, 1541 / Source: https://www.retro-programming.de/retro-welt-2/hardware/meine-altertumlichen-geratschaften/c64/laufwerke/


Quite usual disposition on Apple II with 9" monitors.

Apple II+


Yes, of course external disk drives were often stacked. The LaCie 'Joule' external disk tower was a vertical stack/rack for drive modules,depicted here and many external disk cases were given interlocking features (feet or molded plastic shapes that would keep a stacked unit from sliding off).

  • those don't seem to be floppies, though.
    – scruss
    Apr 8, 2019 at 15:54
  • Until USB came along, no Mac supported multiple externals except SCSI (usually hard disks, optical, or super-floppy); there was only a connector for a single floppy external, so no stacking issue there.
    – Whit3rd
    Apr 8, 2019 at 21:29
  • the question wasn't limited to Macs, though
    – scruss
    Apr 8, 2019 at 22:24
  • 1
    @scruss The answer isn't limited to Macs, either; SCSI allowed a half dozen externals, or more, on any suitably equipped computers; SGI, DEC, Sun, IBM, all had SCSI externals.
    – Whit3rd
    Apr 9, 2019 at 6:01

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