Parallel port CDROMs are quite rare and slow.
External SCSI port CDROMs will have the same speed as internal ones.

However, the AVA 1505/1515 does not support DMA transfers.
If your computer has PCI slots, add an Adaptec 2940.
If not, you'd better use an Adaptec 1542C.

Disruptor wrote on 2020-06-20, 22:58:

Parallel port CDROMs are quite rare and slow. External SCSI port CDROMs will have the same speed as internal ones. […]
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Parallel port CDROMs are quite rare and slow.
External SCSI port CDROMs will have the same speed as internal ones.

However, the AVA 1505/1515 does not support DMA transfers.
If your computer has PCI slots, add an Adaptec 2940.
If not, you'd better use an Adaptec 1542C.

Instead of an Adaptec 2940 variant, you might want to consider an Adaptec 2930 variant, they are cheaper and should work just as well .

16 bit isa cards only. I guess the DMA transfer will be necessary to not bog down the machine by not relying on the cpu?

I see some parallel port cd rom drives that are cheap enough on the lovely ebay. but again have heard the speed is not great. Glad to know scsi is the way to go, but sad to hear that the card I have in the PC is useless for what I want to do with it!

You can always buy and use the external scsi drive while you look for a new scsi controller

IDE CD/DVD drives are plentiful and cheap compared to SCSI ones. Why not get an IDE drive ? You probably already have an IDE hard drive on a cable, so you could just connect an IDE CDROM as a slave .

darry wrote on 2020-06-21, 00:56:

IDE CD/DVD drives are plentiful and cheap compared to SCSI ones. Why not get an IDE drive ? You probably already have an IDE hard drive on a cable, so you could just connect an IDE CDROM as a slave .

This is a vintage "all in one" so to do that I'd have to have extra cables that are supposed to be. "internal" hanging out of the case. There is no good way to add any additional drive to this computer.

I have other PC's with cd rom drives. But i'd like to "complete" this rig. It only has two ISA slots, I've got one reserved for a sound card and as far as "period correct stuff" an extra port to interface with an external drive would be right on the money.

chrismeyer6 wrote on 2020-06-21, 00:38:

You can always buy and use the external scsi drive while you look for a new scsi controller

Thats not a bad idea at all. I've been hunting for a good cheap one that does atleast 8x speeds. Wondering at what point the bus becomes the limiting factor vs the cd rom drive speed.

joeblowv1 wrote on 2020-06-21, 01:56:

This is a vintage "all in one" so to do that I'd have to have extra cables that are supposed to be. "internal" hanging out of th […]
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darry wrote on 2020-06-21, 00:56:

IDE CD/DVD drives are plentiful and cheap compared to SCSI ones. Why not get an IDE drive ? You probably already have an IDE hard drive on a cable, so you could just connect an IDE CDROM as a slave .

This is a vintage "all in one" so to do that I'd have to have extra cables that are supposed to be. "internal" hanging out of the case. There is no good way to add any additional drive to this computer.

I have other PC's with cd rom drives. But i'd like to "complete" this rig. It only has two ISA slots, I've got one reserved for a sound card and as far as "period correct stuff" an extra port to interface with an external drive would be right on the money.

chrismeyer6 wrote on 2020-06-21, 00:38:

You can always buy and use the external scsi drive while you look for a new scsi controller

Thats not a bad idea at all. I've been hunting for a good cheap one that does atleast 8x speeds. Wondering at what point the bus becomes the limiting factor vs the cd rom drive speed.

Good point about the aesthetic aspect, I had not realised therr were no drive bays . SCSI it is then .

Fun fact: some older non PC computers actually used ribbon-like cables externally for connecting peripherals . I am not trying to change your mind, just bringing it up as a curiosity .

I would go for SCSI, though i always hated the external cd drives that looked like they were shoved into a random external SCSI enclosure.

There were a few that looked the part without ruining the looks of it, like the Toshiba 4101S or some HP and Philips models

Toshiba XM4101S

HP - Agilent - Keysight C2943A

Master_Shifu wrote on 2020-06-21, 04:50:

I would go for SCSI, though i always hated the external cd drives that looked like they were shoved into a random external SCSI […]
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I would go for SCSI, though i always hated the external cd drives that looked like they were shoved into a random external SCSI enclosure.

There were a few that looked the part without ruining the looks of it, like the Toshiba 4101S or some HP and Philips models

Toshiba XM4101S
442997818b4466217f243bce652e4870.jpg

If you like caddies. Personally, I am not a fan .

Yamaha made some good looking external SCSI CD-R drives, IMHO, and a couple of ugly ones too .

https://www.worthpoint.com/worthopedia/yamaha … cd-rw-305401956
https://www.amazon.ca/Yamaha-CRW-F1ZSX-44x24x … r/dp/B071LPBCCJ

EDIT: The last HP one looks like it was spawned through an unholy union between an early inkjet printer and an egg slicer .

darry wrote on 2020-06-21, 04:57:

EDIT: The last HP one looks like it was spawned through an unholy union between an early inkjet printer and an egg slicer .

The later XM4101S was a regular tray design like in the second picture, had one that was a perfect match to a macintosh SE/30. But they are harder to find. Found mine just in a lucky search on eBay for an external SCSI cd drive. Only had Toshiba External SCSI Drive in it. no model numbers or anything. the good part was it was only 40 euro including 25 euro shipping with all the bits and pieces!
NEC also made a few very nice external ones, though you would easily mistake them for early Discmans instead of cd drives.

Have a 32 speed parallel port BackPack cddrive in my 286. It works just fine and a piece of piss to setup as is the parallel port LS120 drive daisy chained to it... No need for caddys and if the cddrive dies I can easily replace it. Can use both drives at the same time or use them individually. In fact iirc I can have up to 5 devices daisy chained this way with no need for device no.s to be set or terminators.

My external cdrom drive cost $nz5 plus postage with no cable or psu. Had some parallel port flat bad scanners so used the cable from one and a suitable psu from my stash. As you can see from the pic the cables are not visible at all.

Hm, in the interest of not taking up a massive amount of space. Does anyone have any feedback on those smaller "discman" style scsi drives? I see a handful of panasonic ones on ebay at around 8x speeds, wondering if they would fit the bill as they're the most affordable

I do love the hp drive because of how purely ugly it is.

Like the Panasonic kxl-dxxx series?
If you buy a working one it should work without issues, an untested one though, you're taking a chance to end up with a dead one.

The 6360 based Adaptec cards are no slouch. Even in PIO mode they will destroy a parallel port

Not really the most beautiful solution, but I once attached an externally placed internal IDE drive to my IBM model 30-286:

Sound card with onboard IDE. Attached the IDE ribbon cable to it and got it out thru a slot cover youth openings.
Power came from some ISA breadboard card where the power cable was attached (soldered) to the right contacts on the ISA edge. It just worked for what I wanted to do, maybe it works for you too 😀
When not used you can store the CDROM drive away from the machine to make it look good again.

Eventually detached it to fit the CDROM and sound card in another machine.

lolo799 wrote on 2020-06-21, 16:46:

Like the Panasonic kxl-dxxx series?
If you buy a working one it should work without issues, an untested one though, you're taking a chance to end up with a dead one.

Good to know, sounds like they're a bit flakey?

Great info in here though people! Thanks again

Panasonic/Matsushita is a good brand but those drives are old.
My point is that it's probably better to get a 5.25" enclosure for scsi (or parallel) drives so you can easily change the drive if it shows signs of failing or if it can't read cd-r or cd-rw for example.
Even if generic enclosures are larger than the portable discman style drives, atleast you can use them longer.
Or you could go pcmcia but it has downsides like the larger ram usage...

Just my 2¢
Network is much more useful then CD drive on a 486.
You can copy the files over or even share a CD drive from another PC to install things once windows is installed.
Early dos game's only really want a CD for CD audio, something you may not get with an external drive.

CD drive can be useful, but I'd either go with onboard SCSI or Parallel and keep that 2nd ISA slot for a network card