If you liked the blinding quality of software engineering, you might also enjoy: the kind of stuff that hardware engineers get away with.
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If you liked the blinding quality control of software engineering, you might also enjoy: the kind of stuff that hardware engineers get away with.
Having finalised the interconnect layout, it was optically reduced to a 10× magnification light-field mask and used to create a complete multi-chip wafer mask using an optical step-and-repeat procedure, as discussed in the section called Generate Interconnect Pattern in Chapter 5, The Ferranti ULA. From this Ferranti produced an initial batch of prototype wafers and invited Altwasser to functionally test and verify the chips in-situ, before they were diced and packaged.
Altwasser was provided with a wafer probe that allowed connection to individual bond pads and made it possible to attach external circuitry with which to test the devices. Altwasser and Ferranti were under extreme time pressure, and carrying out tests during this stage saved a few precious days. However, while performing these tests and visually inspecting the interconnection tracks under a microscope, it was discovered that the Ferranti layout engineer had made an error in the interconnect layer whereby the clock output from the early counter stages was not connected to the later stages. Fortunately, and against all odds, a tiny fleck of dust had fallen onto one of the devices of the multi-chip wafer mask at exactly the point at which the missing interconnect should have been, despite the usual clean room conditions of a semiconductor plant. This artificial bridge prevented etching of the aluminium at that point, connecting the
clock to the later counter stages and allowing Altwasser to complete his full test suite on this one die, successfully proving the entire chip design of the 5C102E ZX Spectrum ULA.(Page 74 from The ZX Spectrum ULA: How to Design a Microcomputer by Chris Smith.)
:blobcatreading: #bookstodon
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react loading skeletonreplied to Riley S. Faelan last edited by
@riley lol (lmao)
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react loading skeletonreplied to react loading skeleton last edited by
@riley as someone with a phd in software engineering though I feel like I should defend software engineering and say that we know HOW to make reliable software but liek no one spends the money to do it
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Riley S. Faelanreplied to react loading skeleton last edited by
@ionizedgirl One of the greatest recent eye-opening ironies has been, at least to me, how only after the errors of ChatGPT convinced rich people to invest in designing expensive-to-break systems with undo buttons.
When a human makes a mistake, her boss gets to scapegoat her, but scapegoating a machine is a taboo. A machine gets the benefit of reparative justice instead.
