Author Topic: External Swappable SD Card Hard Drive Mod(concept)  (Read 372 times)

Online TheGrandPubaa

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External Swappable SD Card Hard Drive Mod(concept)
« on: July 25, 2018, 08:50:48 AM »
While I am waiting for my refund process to go through on my 1 day's worth of Mac Mini ownership and while my new Mac Mini deal finalizes, I wanted to think about a relatively simple idea I had and get some feedback on it before doing any actual modifications. At some point, I plan to experiment with an SD to IDE adapter I bought a few years back(originally for use as a PS2 hard drive, and that worked great if you didn't exceed 128GB - which I did with a 256GB card, so even though it could detect higher memory, the adapter wouldn't be able to write it) and a SanDisk Ultra Plus microSDXC UHS-I 64GB card. It's amazing how cheap this memory is getting. I remember spending over $60 dollars for two 32GB SD cards that eventually went into my halfway deceased Pandora. But I digress.

I plan to do some rudimentary testing on the read/write speed and overall feel of the system while running on SD, and whatever benchmarks I can run, but if it works at all, I imagine it will be fine and usable if not overly fast. I started thinking about how cool it would be to be able to swap the SD card out without having to putty knife my way into the case every time. There are some use cases that would justify this, such as running a different OS on each different SD card, simplifying boot configurations immensely. I know there are concerns about long term damage to the cards due to heavy writing/logging/caching in, say, OS X or Linux, and this could be mitigated by keeping backup images and simply popping in a new card if the old one ever starts to fail.

https://www.adafruit.com/product/3687

I haven't played with one of these SD extender ribbon cables before, but if there aren't any additional instabilities as a result of using it, that would help maneuver the card slot into whatever position made the most sense for the mod. The big question is how to get the slot externally accessible with a minimum of damage to the case. I'm not against case modification on a fundamental level, particularly if it improves function, but I also wouldn't necessarily want to ruin the elegance of the Apple design. If this proves feasible and I decide to pursue this more vigorously, I may get a parts machine or a parted out case and try modifying that.

For the purpose of conversation, let's assume that I did decide I was going to go after the case with my dremel and I am going to mount the SD card slot where it is externally accessible. What location on the case makes the most sense? The rear would be preferable since it would be the least obvious, but that area is particularly busy with all the ports, the fan shroud, and just behind the rear of the case is the IDE peripheral card, so I don't think that will work based on my limited firsthand knowledge of the inside of a Mac Mini G4. The top of the case is a possible candidate since that would involve cutting through plastic as opposed to aluminum and could be easily accessible for swapping the cards, but the optical drive seems like it would get in the way unless there is some space towards one of the rear corners. I seem to recall that the front of the case is pretty busy as well with the LED and speaker, as well as the plastic housing for the IDE peripherals and fan, so that might not work either. Perhaps there is room to mount the card slot on either side of the case? *Well, I forgot about the RAM, obviously, so it would have to be the opposite side.

I attached a photo from iFixit and i'm wondering if the space towards the rear of the optical drive where it chamfers(if that is correct) inward could be a possible candidate. This is where the Airport antenna normally goes, I believe.
« Last Edit: July 25, 2018, 09:04:34 AM by TheGrandPubaa »

Offline macStuff

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #1 on: July 25, 2018, 01:54:55 PM »
neat - thanks for sharing

Offline Fury deBongo

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Re: SD Card HD Mod
« Reply #2 on: July 25, 2018, 04:37:13 PM »
Near that upper left, red circle on the above image from iFixit… it looks like you might be able to route that cable through the area where the cable-lock security hole is on the back I/O white plastic panel. (Just above the headphone jack.)

After routing-out that hole to accomodate the small flat ribbon cable of the SD card extender, there’s that thin metal shroud / shield that would also need to be “snipped a bit” to allow passage of that small cable on into the Mini.

Then, you might be able to route that cable between your RAM and that black plastic, upper left (red circle area in pic) screw mount. OR (I’m not taking this thing apart any further now) you might be able to “shave” a bit off of the lower portion of the circuit board that the optical drive and HD plug into (to allow that Extender cable to pass under it). From what I can see without further disassembly, it appears that there is no circuitry on the very bottom of that board.

Of course, I’d prefer to route it under the circuit board to avoid twisting and then routing that extender cable that close to the RAM.

But, whatever the route… are you not still going to need something to convert (or “bridge”)
from that small ribbon cable to the existing 44-pin HD connector?

And then… there’s always the cost/performance comparisons between CF and SD. ;)
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Online TheGrandPubaa

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #3 on: July 25, 2018, 09:25:57 PM »
I thought I had posted this after thought earlier but I guess I didn't. So here goes:

I had another thought. It's definitely inelegant, but if I were to do some soldering, I could probably fit a small cable(a series of thin kynar wires) through the Kensington lock port and route an SD card extender that way without having to cut into/modify the case at all. I could mount the sd card slot on the side with 3M mounting or velcro strips that way. A little ugly, but easily reversible and still convenient if it works.

But, whatever the route… are you not still going to need something to convert (or “bridge”)
from that small ribbon cable to the existing 44-pin HD connector?

And then… there’s always the cost/performance comparisons between CF and SD. ;)

Of course. I mentioned the adapter I have/plan to use earlier, but I suppose I never actually linked it:

https://www.amazon.com/gp/product/B00DGNYXQ0/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

I've used it in the past to boot a PC, play games on a PS2, and as the install source for Windows 2000 for temporary use on an HP Thin Client. So i'm hopeful it will work. Didn't cost me anything extra if it doesn't, though. It will plug directly into the 44 pin IDE port on the Mini and shouldn't need any additional mounting. I will obviously try and run some benchmarks on it, and my assumption is that it won't be as fast as CF, but the 64GB card cost 19 dollars, so it's a cost effective alternative in my mind. I just looked on Amazon out of curiosity, and if I am willing to go with a no-name brand, there is a 64GB CF card for $34, although I don't yet know if it's IDE compatible.

*Additional thought*

The more I look at that lock port, the more I find myself wondering if that could be the spot to attack. With a minimum of modification, I could potentially fit a female micro sd card slot there and simply route the ribbon cable to the hard drive adapter. This will require some thinking and staring at the case for a few hours...
« Last Edit: July 26, 2018, 07:59:11 AM by TheGrandPubaa »

Offline Fury deBongo

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Like this...?
« Reply #4 on: July 29, 2018, 09:20:15 AM »
This will require some thinking and staring
at the case for a few hours...
Who (among us all) has not done something very similar
to that which is portrayed in the attached image?

Already bounced it off Pubaa and I doubt that Clooney
would mind (considering the spirit of it). If I'm wrong
in that assumption... down it shall come, post-haste.
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Online TheGrandPubaa

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #5 on: July 29, 2018, 04:15:33 PM »
Indeed, just like that but without the fatigues or the wicked mustache.

I currently have the case apart but the Mini is running. I'm taking some wordier notes, but i'll give the tl;dr version here. I used V8 of Ross's installer, which worked without any problems at all. The MicroSD card is a 64GB Sandisk Ultra Plus UHS-I and the SD to IDE adapter, linked previously in this thread, appears to be a Sintechi adapter though I forget if it is unlabeled/generic or not. Installing the new "drive" was easier than removing the old one and was painless. OS 9 initialized the disk without complaints, I copied over the goodies from the Extras folder of the disc, set it to restart from the hard drive, rebooted, did the first boot thing, restarted again, and timed the boot from when I heard the chime to when the desktop was loaded as taking 40 seconds. I didn't do any timing or benchmarking of the 40GB hard drive, though I may put it back in to do so while i've got the case apart. I have yet to benchmark the SD card, but my initial impressions are good.

About possibly mounting an SD extension cable/ribbon to the rear of the case: I could either clip off or bend back the metal piece of the kensington lock that is part of the top shielding, and I would also have to cut a bit into the black fan shroud plastic that directs airflow out the rear of the case, but it is far enough away from the majority of the airflow(as well as the fan) that I think it could be done without impacting thermal regulation in any significant way. I will obviously also have to cut/file away some of the white plastic housing around the lock port to make room for the secondary SD card slot, but in my head at least, it all seems feasible.

After I do some initial baseline CPU benchmarks, I may conjure up the courage to remove the logic board and desolder the 4 jumpers/resistors to see how stable the Mini is at 1.5GHZ. But, one thing at a time.

*edit: I find myself encountering the frozen mouse cursor bug, so that sucks. I guess i'll need to hotkey the shut down tool; too bad I didn't already do that.

*edit 2: I attached a photo of my MacBench results for CPU/Disk. I didn't take a comparison test with the old hard drive, so I don't know whether this is a good, bad, or neutral result. I haven't overclocked yet either, so this is the stock 1.25GHZ.

*edit 3: Attached is the MacBench results with stock CPU and the original 40GB IDE hard drive. Unless this is one of those tests where the smaller number is better/faster, these results seem to indicate the SD card setup is faster than the stock drive. I just did the basic main test without changing anything, so maybe it's somehow a fluke?

Stock HDD: 1787
SD Card w Adapter: 4868
« Last Edit: July 29, 2018, 05:29:25 PM by TheGrandPubaa »

Online TheGrandPubaa

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #6 on: July 29, 2018, 06:26:33 PM »
That last post was getting cluttered up, so here is the new results I have to show. Mac Mini G4 overclocked to 1.5GHZ, 64GB SD Card HDD.

Processor: 3896
Disk: 5072

 I haven't run any games or anything CPU intensive other than this benchmark, but i'm pleased that I didn't break anything.

Offline DieHard

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #7 on: July 29, 2018, 06:29:03 PM »
Nice Job and thanks for the details :)

We have to start making a full list of compatible adapters that perform well without any issues in legacy macs,  let us know if it runs "cool" with the SD card; I may try your adapter in a few Powerbook G4s

Online TheGrandPubaa

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #8 on: July 29, 2018, 07:09:39 PM »
Followup benchmark results using QuickBench 1.5 attached.

Also, my understanding is that there aren't discrete temperature sensors in the Mac Mini like there were in other Macs of the era and in modern machines, so is there a particular way in which I can monitor the overall effect of the SD + OC other than watching for crashes/shutdowns?

Online TheGrandPubaa

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #9 on: August 10, 2018, 12:06:27 PM »
Just a quick update. I purchased a Micro SD extension ribbon cable from a seller on eBay which arrived today. I took the Mac Mini apart and installed the extender into the SD card slot and routed the ribbon cable around the drive mechanism, up between the optical drive and the RAM, and it's just kind of sitting on top of the optical drive for the moment while I have the computer apart. I tested the Mini for a couple of minutes with some Diablo II and Return to Castle Wolfenstein with no noticeable differences. Putting the ribbon right next to the RAM makes me wonder if there could potentially be a problem of data corruption, but so far it works like it should and solves quite a bit of the routing problem. I will now decide if and how I will modify the rear white plastic of the case to allow for the new card slot to be exposed externally. Playing around a bit with the extension ribbon, I am starting to think the easiest place to fit the card slot would be directly behind the optical drive. This would involve carving a small hole in part of the black drive bracket/housing/whatever it is called, removing a bit of the metal shielding directly behind that, and working on 4 or 5 of the vent fins adjacent to the lock port. The black Micro SD slot(which I could paint white to sort of match the exterior of the case if I felt the urge) would protrude from the rear of the case about 8-10 millimeters to make it easier to get at the card(the slot has a click locking mechanism).

https://www.ebay.com/itm/Flex-Extension-Cable-Extender-Adapter-TF-to-Micro-SD-card/173198380715?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

*edit: Added pics. Seems to work fine. I'll eventually get around to making a card for another OS.
« Last Edit: August 11, 2018, 04:43:40 PM by TheGrandPubaa »

Online TheGrandPubaa

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Re: External Swappable SD Card Hard Drive Mod(concept)
« Reply #10 on: August 12, 2018, 10:06:51 AM »
I've spent a few hours playing around with a second SD card and I haven't encountered any operational issues at all. I briefly installed Lubuntu on an 8GB SD, but it was so laggy as to be completely unusable - I guess running it without X might have been okay, but I am more of a GUI guy so that's not going to work for me. I would like to try one of the BSD variants since there doesn't seem to be any sign they will drop support for PPC anytime soon.

I installed the latest MorphOS instead, which is something I have been wanting to play around with for years but I never had the right hardware. It boots extremely fast. Possibly twice as fast as OS 9, which surprised me as OS 9 was fairly speedy for me. I just did a reboot and timed startup from chime to the Workbench icons loading and got 22 seconds. So that's impressive. I've done a bit of tweaking of the settings and tooled around with OWB and the fullscreen YouTube fix. If you are willing to jump through a few hoops, I find you can get smooth fullscreen YouTube video playback at 360p, which I don't think I have seen on a G4 since YT first launched maybe? It was always choppy on my iBook G4 back in the day from what I recall, so this is pretty cool.

Downside is, of course, that MorphOS requires registration at 79 euros to disable the 30 minute operation time limit. I will have to do a lot of tinkering to decide if it's worth it for me to spend more on the OS than I did for my Mini, but it does certainly have potential.

Overall, I am quite pleased with how the mod has turned out so far. Sure, the read/write speed isn't as fast as an SSD, but it is super convenient to have the ability to swap the hard drive out without having to use a putty knife every single time, and I haven't had to fight with boot loader configuration at all.