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DaynaFile hackiness


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As documented in my "Liberation" thread about my SE/30 with Radius Pivot Display, the haul also included a DaynaFile dual-5.25" drive external SCSI unit.

I had never even heard of these units until getting this one - it seems like a great accessory, a SCSI peripheral (so no funky controller cards needed the way Apple's PC Drive kit did,) that has both 360 KB drive and 1.2 MB drive in it. (If you aren't familiar with PC 5.25" drives of the era, 1.2 MB drives had the oddity that because the high-density format wrote to the media at a different magnetic power level than 360 KB drives did, they weren't 100% backward compatible.  Yes, they could fairly reliably read 360 KB disks, and they could format and write to 360 KB disks with reasonable reliability, those disks, once written with a 1.2 MB drive, were often completely unreadable on a native 360 KB drive!  Hence the usefulness of having both drives at a time when both types of disks were still in common use. Even IBM acknowledge this, shipping the PC-AT with one 360 KB drive and one 1.2 MB drive by default, rather than only using a 1.2 MB drive.)

That wall-of-text done, the major problem with my DaynaFile is that it didn't include a power supply brick.  It uses a DIN-5 connector (similar to the IBM PC through AT keyboard plug, or the Apple Iic serial ports,) that carries both 5v and 12v from a power brick.  Unfortunately, I cannot find any documentation on the pinout of that connector - rather important to make sure I don't fry it!

 

I found a positively ancient fan page on it, and beyond regular hope, I emailed the the address on it to see if he happened to have the pinout (and if the email address was even still valid.). Amazingly, he responded within a day!  Unfortunately, he's on vacation out of town for two weeks.  He said he would check when he gets back home.  (More than I expected, so I appreciate it.). I have a few 'spare' DIN-5 connectors, and I have an external power brick that delivers both 5V and 12V power over a Molex (hard-drive-style) connector (it came with a USB-to-PATA adapter that died some time ago, the adapter was very small and meant to just attach to the back of the drive, then you'd use the Molex-equipped power brick to plug directly in to the drive as well.) I also have plenty of female Molex adapters from various cables (splitters, extenders, etc,) so I figure I'll just hack together a Molex-to-DIN-5 adapter when I find out the right pinout for the DaynaFile.

 

I managed to open up the DaynaFile, and it's pretty simple.  The two floppy drives appear to be completely standard PC drives of the era. The controller board sits beneath the drives, and is physically separate from the ports on the back, except the power port. It has ports to go to the two drives (on separate connectors, not chained together,) standard 50-pin SCSI port for the cable to the back panel, Molex power out to the drives (with a single-to-dual Molex cable,) a floppy-style power plug to go to the power switch and the SCSI selector on the back panel (it is similar to the floppy power port, but isn't exactly the same.)

 

Unfortunately, with the DIN-5 power port directly on the controller board (the only external port directly on the controller board,) I can't just bypass the DIN-5 port.  In addition, it's a thick PCB, and most of the traces from the power port are on internal layers. I can't trace any of them directly to the Molex port to figure out which pins are which!

 

Ironically, while going through a box of manuals after my dismantling, I happened upon manuals that had obviously come from my dad's work that he gave me.  One of them was a still-shrinkwrapped manual for the DaynaFile II!  Complete with original driver disk inside.  Hah!  For not having heard of the product before a couple days ago to finding that I've had a manual for one in my collection for probably 15+ years...  (My dad was a bit of a vintage computing collector, too, largely stuff his work was throwing out - he gave me most of his collection in '99-2000 era, when my mom started insisting he clean out their basement. Ironically, now she sees MY basement and just sighs.)

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(If you aren't familiar with PC 5.25" drives of the era, 1.2 MB drives had the oddity that because the high-density format wrote to the media at a different magnetic power level than 360 KB drives did, they weren't 100% backward compatible.  Yes, they could fairly reliably read 360 KB disks, and they could format and write to 360 KB disks with reasonable reliability, those disks, once written with a 1.2 MB drive, were often completely unreadable on a native 360 KB drive!  Hence the usefulness of having both drives at a time when both types of disks were still in common use. Even IBM acknowledge this, shipping the PC-AT with one 360 KB drive and one 1.2 MB drive by default, rather than only using a 1.2 MB drive.)

 

Just for the heck of it I'll point out that the major reason for the backwards compatibility write glitches wasn't the write current; the drives adjusted power appropriately if running at the lower density data rate. (Although a notable problem with the drives was there was no sensor to tell the drive what sort of media was mounted so it was easy to accidentally format a DD disk with a High Density format, which both wouldn't work and could screw up the media so it couldn't be reformatted unless you ran it through a bulk eraser.) The issue was that the HD drives used 80 tracks instead of 40, with a correspondingly narrow read-write head. This wasn't an issue for reading but if you wrote back to the disk the skinnier head would only partially overwrite the existing data, at least so far as the lower density drives were concerned. The only way to reliably transfer data back was to use a brand-new disk formatted (with the proper switches, of course) and written from scratch.

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Those drives really were a strange choice for IBM. Another oddity of them is they spin at 360 rpm vs. 300 rpm; the reason was that the drives were really designed to be drop-in replacements for the old eight inch floppy drives, and this explains why their capacity is 1.2MB instead of the 1.44MB you'd expect from doubling both the number of tracks and the data rate.

 

Notably there were a number of systems going back to the late 1970's that used 80 track double-density drives (sometimes these were called "quad density") and could store around 720k on a double-sided disk. It's sort of interesting that IBM's disk BIOS didn't support a 720k format for low-density disk media in the 1.2MB drives, the hardware totally supports it. I imagine they concluded that offering that would have confused users even more, but it would have been a handy way to double the capacity of existing media, which might almost justify the data transfer hassles for AT users.

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If you have a multimeter, you should be able to use it in continuity mode to trace from the DIN to the Molex. I assume it won't be going through any DC to DC converters or whatnot that might interfere with that, the molex should be connected directly to DIN.

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  • 4 weeks later...

I also had a DaynaFile without a power supply. I don't remember the pinout, but here's what I've done:

- with a multimeter i continuity and one probe to the shield of the SCSI connector I started looking for the ground pins

- next I checked the voltage pins (as Compgeke suggested) between the molex connector and the DIN.

Lastly I picked up one of those external hard drive / cd drive power supplies, the old ones that output 5 and 12V, chopped the connector and soldered the wires to a DIN I had lying around.

 

The DaynaFile must have been a very popular device, I've seen a lot of macs on sale with it included in the lot.

In the end I got rid of mine because I have an Apple PC 5.25 drive and both (SE ad Mac II) cards. I think the drive has the same connector as the IBM external ones.

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I have one as well. Likewise the power brick is missing. I'd throw it on the bench and probe it tout tonight but my desk is currently in three pieces as I renovate. Poke me later though and I should have the full ability to get you a pinout and some pictures.

Edited by CelGen
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my DaynaFILE 1.2MB & 360k, original guide, power supply Elpac, 220V, 45 W

+ 5V, +12V, -12V

 

Never tested it due to the lack of usable PC floppies

 

 

Dos Mounter Plus 4.0 app&manual

http://macintoshgarden.org/apps/dos-mounter-plus-40

System 6.x - System 7.0 - 7.6

Runs in Mac System 6, where it is likely to be most useful.

For systems 7+ which can run Macintosh PC Exchange, its likely to clash with that software and cause problems.

Its probably better to use Apple's PC Exchange software only in that case (especially with Systems 7.5 or newer, where PC Exchange is included with the Mac OS).

 

 

Some extra info :

DaynaFILE 3.0 & DOS Mounter 2.04

http://www.danielsays.com/ss-gallery-macintosh-daynafile-dos-mounter.html

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  • 1 year later...

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