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Thursday, July 24, 2008

Non-Locking Connectors Considered Harmful

A rant, a sad story, and—gasp!—some possibly useful suggestions.

What results from not having both eSATA cables properly plugged in at startup time.

All hail the progress of inexpensive CE (Consumer Electronics) and IT (Information Technology), and the cost benefits they bring to production! Unfortunately, they also bring some gotchas, like a plethora of non-locking connectors. Most us have probably struggled with the diminutive and easily-disturbed four-pin FireWire connector, and who hasn’t had a 1/8-inch stereo audio miniplug unplug itself at some point? 

But the threats I’m here to discuss are even more insidious than these:  ExpressCard34 slots, and eSATA cables.

I have a MacBook Pro into which I plug one of two ExpressCard34 devices, a Duel Adapter for reading Panasonic P2 cards, and an Apiotek dual eSATA II controller, which I use to connect an OWC dual SATA drive enclosure stuffed with two 500GB drives, configured as a soft RAID using OS X’s built-in support.

Now, when I use the ExpressCard34 slot for Sony SxS cards, it works just fine: I pop the card in and push it in until it clicks. After transferring data and ejecting the card from the Desktop, another inward push toggles the hardware ejection spring, and the card pops out.

The same physical operations install and eject the Duel Adapter and the eSATA adapter, but unlike SxS cards, these devices stick out from the Mac. The Duel Adapter has a fat, hardwired cable with a PCMCIA card reader at the end, and the eSATA adapter has a pudgy lump into which two eSATA cables are plugged. The trouble is that there’s nothing aside from connector friction holding ExpressCard34 adapters in place, and it’s very easy to pull them out by accident, or just bump them and loosen them. Mass-storage devices, like P2 cards and RAIDs, really don’t like to be disconnected this way, and file-system corruption and data loss can easily occur.

My fix is to gaffer-tape the danged things in place. There’s plenty of space on the top deck of the MacBook Pro to lay a strip of tape, thanks to Apple’s infuriatingly lame use of a 12” keyboard on a 15” machine [1], and there’s space below, too, so a couple of criss-crossed strips of tape wrapped around the base of the Duel adapter (or the sides of the eSATA controller’s sockets) and then stuck to the computer will secure the things. 

Ah, but eSATA cables, now, they’re just downright evil. eSATA cables plug in with a simple friction fit; there are spring-loaded fingers in the connector shell designed to retain the plug, but they’re no more effective than the similar fingers in an HDMI socket (a friend calls HDMI plugs a “self-ejecting” technology). Furthermore, an eSATA cable doesn’t have to be unplugged very far before it loses connection, so a quick visual check often isn’t good enough to verify proper plugging. I haven’t unplugged a cable by accident when my eSATA RAID is running, but on a couple of occasions I’ve not completely plugged in both cables all the way when setting the thing up, or I’ve jostled a cable slightly loose while repositioning the system on a table.

I’m lucky: I’ve got my RAID configured as RAID 1 (mirroring). What happens to me when I haven’t double-checked my eSATA cables is that the RAID comes up damaged, but repairable once I push the errant cable fully home. The rebuild takes an annoyingly long time, but at least I’m given the opportunity to reflect on the error of my ways, and vow to check my connections better the next time. If I had my RAID configured for RAID 0 (striping) instead, I’d probably be out of luck, and I could kiss my data good-bye.

If you’re running any sort of cable-per-drive RAID (such as the Sonnet Fusion F2, or something similar to my homebrew rig), it really pays to double-check connections by manually reconfirming that all cables are pushed fully in before firing up the system.

If you’re looking for a new external SATA RAID for location use, it’s probably worth considering one with port multiplication capability, so that a single eSATA cable connects the RAID to the computer. That way, if you unplug a cable, the RAID goes away, and has less chance of corruption from a single disconnected drive.

[1] All Mac portables use keyboards that neatly fit the discontinued but much-loved 12” Powerbook, no matter how much real estate the laptop affords. These compact keyboards lack dedicated PgUp, PgDn, Home, and End keys, so those of us who actually use keyboards for real work are always having to press the danged Fn key to get to these frequently-used functions. For a company that’s made its reputation on design and usability, this is criminally negligent. Haven’t they ever seen an IBM/Lenovo ThinkPad keyboard, fercryinoutloud? Oh, don’t get me started…

[2] The title is a nod to Edsger Dijkstra’s 1968 letter Go To Statement Considered Harmful, famous in computer programming circles and often imitated. Sorry, I’m a geek; deal.

Hardware •

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couple tidbits Adam:

1.) I’ve got a locking HDMI cable I need to review, so some folks are wising up about these issues. Hopefully someone will do locking eSATA similarly.

2.) For the RAID sync issue, I’ve also heard numerous complaints about Apple’s Disk Utility losing sync and being bad about informing you about it - was this fixed sufficiently in 10.5?

3.) ...which is why I’ve long used SoftRAID for my RAID 0/1 needs, as it is better about reporting problems, faster at fixing them, AND does striped reads for better performance! I don’t know how much Disk Utility has caught up, but with 10.4, SoftRAID was way better. Dunno about 10.5.

-mike

Posted by Mike Curtis  on  07/24  at  08:43 PM

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Hi, Mike!

Locking HDMI: I covered a locking HDMI cable (from http://lockinghdmi.com, oddly enough!) back in April:
http://provideocoalition.com/index.php/awilt/story/locking_hdmi_cables/
Is yours a different one? I found the one from lockinghdmi works on the RED ONE, but does in fact need a thin screwdriver or a putty knife to unlock it, given the recessed socket on the RED.

I don’t know of a good way to make a locking eSATA cable in the same manner, especially since eSATA sockets are often stacked right above one another, making access to the unlocking button very difficult when multiple cables are plugged in. Still, one can hope… folks came up with locking cables / collars for FireWire 400 (the six-pin variety) and FW800 cables can be supplied with lockscrews (assuming you can find appropriately-equipped FW800 sockets). Perhaps a lateral latch, instead of a vertical one?

As to 10.4 vs. 10.5 software RAID: my MBP is humming along nicely with 10.4.11 / QT 7.4.5, and runs current FCP, Aperture, Panasonic, Sony, and RED software without a problem (I have a 1st-gen C2D with the nice ATI graphics, not the cranky nVidia graphics of later MPBs: even REDCine runs smoothly, without crashing), so I’m not about to change it, grin.

I doubt SoftRAID could handle a partially-unplugged drive cable any better than MacOS can, and every case so far where my RAID became degraded, it was a loose cable at fault. Nonetheless, you’re not the first to sing the praises of SoftRAID; if I need to do this sort of thing again, I’ll look into it, thanks!

And while you’re at it: write up your EX3 shoot, willya? I still haven’t seen one, and here you’ve gone and used one with Zeiss glass and an s.two… tell us about it!

Posted by Adam Wilt  on  07/24  at  09:19 PM

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