My First Disk Drive

I see I remembered some details wrong, including the number of platters (it’s 6, not 5).

Quoting the IBM article:

The IBM 1311 Disk Storage Drive provided storage for 2 million characters. Developers of the 1311 engineered twice the recording density of the IBM 1301 Disk Storage Unit by reducing the space between the head and the disk by about a factor of two.

The 1311 used the IBM Disk Pack (later designated the IBM 1316 ), an interchangeable package containing six 14-inch-diameter disks in a four-inch stack, weighing 10 pounds (seen above in the man’s left hand). Each disk surface contained 20 pie-shaped regions. Sectors were segments of track lying within a region, and were the smallest addressable unit, with a capacity of 100 characters. Average access time to any sector was 250 milliseconds, which could be reduced to 150 milliseconds with an optional direct-seek feature. The disks were rotated at 1500 rpm, tracks (50 to the inch) were recorded at up to 1025 bits per inch, and the usual head-to-surface spacing was 125 microinches. The ten recording surfaces provided in normal usage a storage capacity of 2 million characters, the equivalent of approximately 25,000 punched cards or a fifth of a reel of magnetic tape.

We had the “direct-seek” feature, which as I remember it meant the heads didn’t return to the outer edge before starting the next seek.  Note those units—some of you are perhaps old enough to remember milliseconds!

Only 1,500 RPM.  It’s gradually gone up, so that enterprise high-performance rotating disks today are 15,000 RPM (but lots of people needing that kind of performance are using SSDs instead).

As I recall the 1401 didn’t use the fixed sectoring; or maybe what we used was layered on top of that or something. It’s been a while now. My memories aren’t precise, but we read records considerably bigger than 100 characters as a single operation, and didn’t have to specify the size on each read (I think it was formatted into the pack somehow).

IBM archives article

Spatchcocked! (What a weird word)

Instructional videos are such a mixed bag. Setting aside the people who don’t know as much as they think they do, and the people who can’t write their way out of a wet paper bag (because those are problems with text instructions also), the basic problem with video is that it moves at the rate chosen by the producer. (Yes, I have software to play videos at multiple times that, but not everybody does.)
 
However, some things involving physical manipulation are much easier to learn when you can see it being done (for many learners; we vary).
 
Here, for example, is Alton Brown showing how little you actually have to do to “butterfly” (or “spatchcock”; where the heck does that come from? Apparently Ireland, then Anglo-Indian, and the OED dates it to 1785) a turkey. This lets you cook a turkey in less time (the video begins by geekily making the argument that he needs to double the surface area to cook it in the time he wants), less space (especially, less tall space), and also it lets you put a much bigger pan of stuffing under it to collect the drippings (he uses vegetables, silly man).
 
And he does it in under 3.5 minutes. (The fact that it’s well-produced also helps of course.)
WARNING: the Food Network’s ads come in hugely louder than the actual video, and hugely too loud, so be prepared to be blasted when you click “play” there!
 

Single-use Camera Project

Not sure where, if anywhere, I’m going past here. But Felicia gave me an old single-use camera at the Minn-StF fallcon, and I shot it when I went out with Ctein after fall foliage the next week.

fgh-20161016-010-001
Photo by Felicia Herman

And I got the negatives back (from Citizens Photo in Portland) last week.

 

Not entirely sure yet what I’ll do with the photos. It’s an interesting project, and it’s startling how bad some of the photos are technically (shot outdoors on a nice sunny day!).