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Showing posts from October, 2014

Serial Ports Revisited

We were trying to test a pair of radios with a data loop-back and were again making the same old mistakes and then wondering what the heck is going on. It is just amazing how many times I have sat down and scratched my head with these things - it feels like I never learn or remember! The mistake we make over and over again is to expect the wrong read/write behaviour from a serial port utility: A serial port is a bidirectional device. A program will grab the device file handle and open the device file either as 'Read', 'Write' or 'Read/Write'. Simple programs like ' cat ', ' echo ', ' bash ' (read, write), ' head ', ' tail ' and ' of ', all open the device file as either ' Read ' or ' Write ', never ' Read/Write '. Complex programs like ' cutecom ', ' minicom ', ' screen ' and ' netcat ', open the device file as ' Read/Write '. So, one ca


A few notes for those new to Linux printing on how to waste perfectly good trees. FTP First walk over to the printer and write down the IP address from the little LCD display. Many network printers have an unsecured FTP server that your company IT is blissfully unaware of (or more likely, they know only True Card Carrying Geeks will use it in a moment of sheer desperation, so they leave it be, even though it can potentially be abused).  If you upload a postscript file to a printer, it will print it immediately - no questions asked.  This works without having anything special installed on your Linux machine. The process works something like this: In your application, select Print to File , then save the file as .  Open a terminal and connect with FTP, then put the file:  $ ftp 172.22.8 . 12 Login: [enter] Password: [enter] ftp> put ftp> bye La voila! CUPS with IPP The CUPS service is maintained by Apple and it works very well indeed.   Usual

Diabetic Foods and Cooking

A few notes on sugar free cooking. As my doctor put it, I am not diabetic, but I should eat as if I am. It appears that the most important dietary modification to diabetes and weight control, is to avoid any food that digests rapidly. At first the list looks daunting: Wheat, potato, rice, alcohol, glucose, sucrose... essentially all common carbohydrates must be avoided - which makes one wonder what is left, since that is about 90% of all the junk on the supermarket shelves! Oats and Rye I don't mind going on a caveman diet of meat, salad and nuts, since I'm a committed carnivore already, but wheat bread is curiously addictive and getting over it is not easy.  There are many different kinds of wheat: Spelt, Durham... so be careful that you don't buy an alternative that isn't an alternative at all. Rye bread is commonly available at bakeries, but it is a little chewy - an automatic consumption limiter. My wife is an engineer of economics, loves cooking and