There was a time when owning a computer meant you probably knew most or all of the instructions it could execute. Your modern PC, though, has a lot of instructions, many of them meant for specialized operating system, encryption, or digital signal processing features.
There are known undocumented instructions in a lot of x86-class CPUs, too. What’s more, these days your x86 CPU might really be a virtual machine running on a different processor, or your CPU could have a defect or a bug. Maybe you want to run sandsifter–a program that searches for erroneous or undocumented instructions. Who knows what is lurking in your CPU?
Continue reading “Find Instructions Hidden In Your CPU”
Every twenty to twenty-five years, trends and fads start reappearing. 2016 is shaping up to be a repeat of 1992; the X-files is back on the air, and a three-way presidential election is a possibility. Star Trek is coming back, again. Roll these observations back another twenty-five years, and you have The Outer Limits, Star Trek, and riots at the DNC convention in Chicago.
History repeating itself is not the exclusive domain of politics and popular culture. It happens with tech, too: the cloud is just an extension of thin clients which are an extension of time-sharing. Everything old is new again.
Continue reading “Variable Instruction Computing: What Is Old Is New Again”
[Geordy] wanted to use some IDE devices but he didn’t have an interface card for his XT system, which can’t handle 16-bit IDE. He looked around for 8-bit ISA controllers but they were hard to find and quite expensive. Lucky for him there’s an open source project that makes a solution to this problem. The XTIDE project brought together a group of vintage computing enthusiasts to design this ISA card. [Geordy] was even able to order a professional PCB from one of the forum members. He ordered the parts an soldered it together, costing about $30 total. He had a friend help him burn the code to the EEPROM but that’s easy enough to do with an Arduino, Bus Pirate, or one of several other methods. Now his grand plans at installing DOS 6.22 have been realized.
[Alex] had an old FM radio tuner card come his way. It used an ISA connector, a standard that went the way of the dodo in the mid-nineties. With the challenge of implementing an ISA-bus to configure the card he set out on his mission. What he came up with is a working radio using the ISA card and driven by a PIC 16F877. Join us after the break for schematic, code, and a few details. Continue reading “Resurrecting ISA hardware”
Check out this visual hardware guide from deviantART member [Sonic840]. It has everything from memory modules, to bus sockets, to power connectors, to an entire array of CPU sockets that have been used over the years. You’re bound to see something in there you didn’t know existed.
Last month we mentioned [bunnie]’s Name that Ware competition where participants try to guess the functionality of a random bit of hardware. We thought you might want to see another example; pictured above is the June 2008 ware provided by [xobs]. You can see a high res version here and an image of the daughter card as well. Be forewarned that someone has already posted the solution in the comments. At first glance there are quite a few interesting bits: board is copyright 1991, the 8-bit ISA connector doesn’t have any data lines connected, just power, and it’s got a lot of analog circuitry. Take a guess and then check out the comments on [bunnie]’s site to see the solution.