Vision Unlimited/LA News

MacBooks and External Disks

by on Jul.12, 2009, under Opinion, Tech Notes

If you are a Mac junkie, like i am, you might have noticed that Apple is once again, playing games with us. When the MacBook series came out a few years ago, the CardBus slots that we had gotten used to on the PowerBooks were gone, replaced by the newer ExpressCard slots. So we started collecting adapters like eSATA, Firewire and USB2 adapters for independent disk interfaces.

And the new MacBook Pros that came out last year didn’t have Firewire (IEEE1394) ports on them. Apple drove us to Firewire from SCSI a decade ago; now they want to take it away? That went over like a lead balloon and Firewire ports are back.

Then, this year, the ExpressCard slots, only a few years old, are gone and replaced by SD card slots. Pardon me, but i have not seen SD cards of any variety that provide anything other than storage. Yeah, cool, you can boot from one, but i can do that from a bus-powered USB drive, when i need to. Apple claims that not more than 10% of us actually used the Express Cards. I guess that means that they expect that 10% to buy 17″ MacBook Pros, the only model with the expansion slot still available.

By the way, the demise of the Express Card slots means that Apple has now done to Sony what they did to Panasonic by removing the CardBus slots. Sony went to the SxS card instead of the P2 card. A lot of good it has done them now. Eventually everyone will go to SD cards, just in time for Apple to find a new standard. That’s the great thing about standards – we have so many of them. (I obviously did not make that up.)

Well, i have a MacBook, which has no expansion slot either. It has USB2 and Firewire 400. I have used it with an IOHD box to capture Apple ProRes and it works, if just barely. It really should be a little faster to meet the system requirements, but the software loads so i use it.

Aside: It’s kinda like the helicopter shoot that i did in New York in the early days of HD. The camera controls and recorders were so big that we needed a Sikorsky helo and a Honda generator to make it work. Yeah, that’s right, a gas generator on a helicopter with the exhaust pointed out an open door. The pilot was a well-known Viet Nam veteran and his idea of weight and balance was to lift off and see if he could keep both the front and back off the ground. We did the shoot and it worked.

Running software these days is kinda like that. We load it up on the best machine that we have available and see if we can keep the machine from crashing and the software from giving us error messages. For video capture, that means no dropped frames.

There are two issues with capturing HD video.

One is the CPU speed – advanced CoDecs (the video compression methods) require more powerful processors than the old DV family ones that we got used to. One way around that is to get an external hardware accellerator, like the IOHD for ProRes. There are a few others that have different mixes of capability but the IOHD is the leader for Mac users. It’s like having a capture and display card plus an external format converter and frame sync, all working with a laptop. Pretty cool.

The other issue is the one that most of us are familiar with – disk performance. Before we had DVCProHD, we were pretty much limited to building RAID arrays for desktop machines with fast disk interface cards. I managed to squeeze four 250GB SATA drives into a dual processor G5 in the days before extra disk bays and got about 700GB of useful, albeit non-redundant, 8-bit, uncompressed HD storage. When we got DVCProHD, we were able to transfer via Firewire from first, tape decks, then cameras, directly to external disks, using laptops. CardBus slots, then ExpressCard slots provided us with the extra, isolated busses that we needed to capture and record at the same time.

But the MacBook, and now most of the MacBook Pros, put us back in the mode of trying to use USB2, which is marginal for disk storage, or coming up with another scheme.

One other scheme is good old Ethernet. While we were looking the other way, a lot of systems, including my trusty old MacBook, got a boost up to Gigabit Ethernet. So i decided to do some tests, and i found that with a fast USB2 drive, i could get about 26MB/sec write speed on the AJA System Test. With a Firewire 400 interface to the same drive, i could get above 30 MB/sec, not bad, but only about 240 Mbps, which is marginal for reliable Apple ProResHQ at 220 Mbps. But when i connected my old G5 to my MacBook via Gig-E and mounted the RAID from the MacBook, i got over 50 MB/s – much more comfortable numbers.

So i got online and found that there are quite a few options for Network Attached Storage using Gig-E interfaces and RAIDed drives. One is the “Intel SS4200-E NAS GETH EXT-HD 4 BAY SATA EMC SS4200-ENA”, which PCMall has for about $240 without drives. This unit uses up to four field replaceable SATA drives and auto configures to a RAID 1 mirror with two drives or a RAID 5 parity set with four drives. You can also manually configure it for a RAID 1/0 fast mirror if you rather. This looks like a good deal and claims to work with the naked Hitachi SATA drives that i use for my backup system. I often find 500 GB or 1 TB drives for $80 to $150.

So the moral of this story is to not forget to look at all the options. Ethernet is not known for its robustness as a capture medium but giving it enough headroom just might make it practical. I plan to give it a try. I’ll let you know how it works out.

It might beat buying a big old clunky laptop.


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