Data recovery

Sound meterI finished my Storytellers Unplugged essay and got it posted on the dashboard so it will appear this Friday without me doing anything else to it, and I also got a fair amount of work done on my Cemetery Dance column, though not quite as much as I had planned.

I spent a good chunk of the last two days recovering data from a digital sound meter my wife is using for her doctoral research. It contained a full 24 hours of data and the transfer program that came with the meter crashed at the exact same point while trying to access the file. A type-mismatch error generated by a Visual Basic component. A corrupt byte, I figured, but there was no workaround with the download software–it was all or nothing. Fortunately, the manual had a table with the RS-232 command set for communications, except the one command I needed wasn’t documented fully. I could open a terminal window, use a USB-RS232 cable and connect to the meter, tell it to do some things, but couldn’t figure out the correct syntax to get at the data.

I downloaded several serial port sniffing programs until I found one that would share the port with the program I was using. From there, I was able to see what commands the download software was sending to the instrument and what was coming back. Through a series of trial and much error, I was finally able to get it to send me the dataset in question. Then I had to figure out how to decode the data, since it came across in hexadecimal form. Finally solved that problem, but I was left with a stream of figures that needed to be converted into floating point decibel values, so I wrote my first C program in a few years and did the required math to turn pairs of two-digit numbers into a sound values–over 1300 of them. I believe I recovered the entire data set, and don’t have a clear idea of why the program was crashing as I didn’t find anything that looked wonky, but that doesn’t matter. The day’s data has been rescued.

We watched two more episodes of The No. 1 Ladies’ Detective Agency last night. I’m sure there are certain sociopolitical elements that we don’t get–the relationship between Botswana and South Africa, for example, but it is a fun series, and Mma Ramotswe’s concept of what constitutes justice and appropriate punishment is fluid and original. The scene with the crocodile was amusing, too.

I finished Vanilla Ride, the new Hap and Leonard novel, this morning. Very existential, in my opinion, and it has some surprising plot developments late in the game that make it one of the best in the series. I went back to Loser’s Town and the story is starting to pick up. Lots of jaded insiders’ opinions about Los Angeles and the film industry.

This entry was posted in Uncategorized. Bookmark the permalink.

3 Responses to Data recovery