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New forum section: IT

Given the number of people here who work in IT in some way, David and I decided to rename the Website section as "IT/Website".

This will be for all the smartphone / laptop / handheld GPS / wifi / bluetooth discussions, and it doesn't have to be aviation related.

Administrator
Shoreham EGKA, United Kingdom

45:78:63:65:6c:6c:65:6e:74

Excellent

EFHF

Bwah. A fine low pass, and with less danger. But do we really need to show forth our ingenuity? KISS, you remember? Works as well for me in IT as in flying.

EBZH Kiewit, Belgium

Now write it out in octal. Should be fine; there are 72 bits which will go into 24 digits.

Administrator
Shoreham EGKA, United Kingdom

Or code it in the Brainfuck programming language:

http://en.wikipedia.org/wiki/Brainfuck

I never heard of that before but it's quite cunning.

It reminds me of writing code for some old Z80-based hardware, where the designer made a mistake whereby the only opcodes that could be successfully fetched from the EEPROM were ones that did not contain any data fields.

So one had to stick to one-byte instructions, and the occassional two-byte ones. But one could not use anything like "add a, 3" because the 3 was coded as a data byte. You had to use "inc a" 3 times.

Data fields within an opcode were OK, because the issue was caused by him using the M1 signal to enable the EPROM. So instructions like "set 3, b" (where the 3 is a 3-bit field within the 8-bit opcode) were OK but "ld a, 3" were not so we wrote macros which would replace "ld a, 3" with "xor a" followed by "set 1, a".

Using this mind-bending bodged hardware, we developed a family of products which made £ millions (1980s)... but nobody got rich because we had up to 35 employees.

Administrator
Shoreham EGKA, United Kingdom

It's nice to see somebody remebers Z80, 6502, PIC, Xilink and all other good stuff when we were very cautions on spedning bits and bytes when programming :)

LDZA LDVA, Croatia

Xilinx? AAAAARRRRRGGGGGHHHHH.

I did loads of FPGA design, eventually mostly ASIC prototyping, up to 1996. In fact I sold the development kit only recently for $200. Original price was about $15k (Viewlogic 4 and XACT); my main client paid for it, indirectly.

Xilinx was a very clever but rather arrogant company in the way they didn't make the design tools backwards compatible. At one point I had to re-enter all the schematics, which was the last straw. Their sales manager sent me a long email saying how one has to move with the times, etc...

The software was also dongled. When the dongle broke, Xilinx refused to replace it, or offer a product which did the same job, which was outrageous. Fortunately some Russian had cracked it, so I continued to run the cracked version.

The "communists" were always the best programmers, and are probably the only really competent low-level programmers today. If you look at the smartphone hacks and cracks, most of them are from the former Iron Curtain.

But FPGAs were interesting work. The last job was developing and protyping a ~5000-gate ASIC, which ended up in a widely sold retail product - a 3.5" diskette which actually contained electronics that faked a 3.5" diskette and had an SD card slot in it. It was eventually made by Toshiba. I still have the printout of the layout on the wall, framed. 3x3mm of silicon printed as 1m x 1m. The whole design consumed a few mA at 4MHz, and had a real time clock section (for RSA security applications of the same chip) which drew about 200nA at 3V, which was quite an achievement and matched only by the DS1302; the clock will run for the shelf life of the lithium battery i.e. 20+ years. The FPGA used was an XC3090.

That was before I discovered flying

Administrator
Shoreham EGKA, United Kingdom

Yes yes, 6502 in the Apple ][, and programming assembler for the PROM (!) on the I/O extension boards, all of 256 bytes big, or a whopping 2048 with some bank switching magic.

But this is fast becoming a place full of old men's memories - didn't we have the piloting pages for that purpose?

EBZH Kiewit, Belgium
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