Brad
@bradthx

Computer Scientist, Electrical Engineer. Loves RF, efficiency, and boating.

 Michigan
youtube.com/user/bradthx
Joined February 2009
1,024 Photos and videos
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Brad
@bradthx
7 Dec 2020
Let's have fun with pagers!
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I've always loved my HP 16500B logic analyzer, been using this fully populated beast for probably 20 years. But wow, this inexpensive DSLogic U3Pro is amazing. Being able to capture and decode an hour+ of i2c comm is amazing.
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Found this tonight, anyone remember installing Windows XP with this media? I probably installed hundreds of machines with it during a part time job in college. It prepped the machine for the first turn on where the end user would finish the installation with their own key.
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It's interesting that over time Texas Instruments had produced a 74LS32 in three different countries.
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I see the NTSB is using ai to generate their illustrations now. While I understand the fuel selector position this illustration is showing, it still hurts my brain to look at it.
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Made some progress on my hardware multiplier today, it has been a few months since I worked on this. I removed an additional bus write by adding a delay line from the second register write to latch the data into the MPY.
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For those curious on the backstory of this project, there is a thread here
Brad
@bradthx
Apr 2
I built a hardware multiplication accelerator for the 8086. It’s an ISA card built around a TRW MPY12HJ parallel multiplier from the 1980s that offloads MUL instructions from the CPU. It actually makes integer multiplication about 2.5× faster on early x86 systems. #retrocomputing #electronics #vintagecomputing 🧵
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As a test, I swapped out the 8088 for an NEC V20. This was an upgrade for the 5150 as it was pin compatible and had a ton of performance improvements, including better MPY performance of only 18 clock cycles. It completed the benchmark in 13.6 seconds, 23% faster than my TRW MPY.
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Yikes. It's probably time to clean off my bench.
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Finally, I have acquired a cheap IBM 5160. Good condition, no hdd which is fine, 640k of ram. Let's see how much work this will be to get going.
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Lol, after some testing, powered it up, and it works. I was not expecting this. Not even a single bad dram chip. This was sold as junk.
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Here we go again, this time Borland Turbo c++ on an 8088 IBM 5150 clone.
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I’ve been thinking a lot about the news of Spirit Airlines shutting down this morning and it's hitting me a bit harder than I expected. I took this picture a few years ago inside the DTW maintenance hangar. A friend of mine was up until this morning, an aircraft mechanic there. People love to joke about Spirit Airlines, but they ran a solid operation. They had a very young Airbus fleet, essentially perfect safety track record, never having an airframe loss, and a lot of good people who knew what they were doing. Seeing that go away sucks when you know people behind it. #spiritairlines 🧵
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It wasn’t these recent things that took them out, more of just terrible circumstances. COVID hit right when they had just expanded. Then the Pratt & Whitney GTF engine situation made it worse. At one point around 20% of their fleet was grounded due to these engines being recalled. This was absolutely brutal for any carrier paying for new jets that can’t fly. I took this photo at DTW in 2024. Six basically new Airbus planes just sitting there mothballed waiting on engines.
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For what it’s worth, I never had a bad experience with Spirit. I don’t fly that often, but the handful of Spirit Airlines flights I’ve taken were all solid. Crews were always professional and awesome, no issues at all. Always nice flights. This pic was from a flight last year on Spirit heading back home from FLL. During peak travel times, flying Spirit saved us thousands of dollars. I will miss this airline.
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Finally, I have my 5150 working and booting. I added an external isa memory card to get the base up from 64k to 640k. XTIDE adapter is booting msdos 5.0 off of a CF card. Dos 3.x would be more period correct, but I wanted some of the more modern benefits.
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I also upgraded the stock bios to GLaBIOS, which so far is working awesome. The whole system boots in just seconds now.
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This IBM 5150 clone has been killing me. Finally from being completely dead, I have it booting and showing signs of life.
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There were a total of 5 bad 4116 ram chips on it, now it's passing every memory test I throw at it.
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