[HN Gopher] The Infinite Loop That Wasn't (2020)
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The Infinite Loop That Wasn't (2020)
Author : tosh
Score : 111 points
Date : 2022-02-04 12:08 UTC (10 hours ago)
(HTM) web link (mgba.io)
(TXT) w3m dump (mgba.io)
| dang wrote:
| Discussed at the time:
|
| _The Infinite Loop That Wasn 't_ -
| https://news.ycombinator.com/item?id=22151036 - Jan 2020 (35
| comments)
| taneq wrote:
| No discussion of infinite loops that aren't would be complete
| without a mention of The Story of Mel:
| http://www.catb.org/jargon/html/story-of-mel.html
| megiddo wrote:
| Thank you! I've been hunting for this story for years.
| falcrist wrote:
| The story was featured on the YouTube channel
| "Computerphile".
|
| https://youtu.be/XS3UBuZ7D34
| kingofkyiv wrote:
| This is an amazing read. I too was looking for this for a
| while.
| xxs wrote:
| I read it when I was a kid (11/12)... along with Real
| Programmers Don't Use Pascal. I was chiefly impressed by both,
| for quite some time I thought both of the them were real and
| represented real(!) values. To this day I can quote quite a bit
| of both.
| bear8642 wrote:
| > both of the them were real ...
|
| Well, Mel's story is definitely real!
| lelandbatey wrote:
| Indeed, Mel is (was?) real and we have a photo of him! If
| we go to Wikipedia for the LGP-30[0], it links to a wiki
| article on "The Story of Mel"[1] which names the titular
| "Mel" as "Melvin Kaye" with a citation, linking to a PDF
| scan[3] of an issue of "The Librazette" where on the first
| page, the photo on the left, in the very back and named
| last of all the people in the photo, is [sic]"Royal-McBee
| Applications Engineer Mel Kaye" standing and smiling in an
| all-white shirt.
|
| [0] - https://en.wikipedia.org/wiki/LGP-30
|
| [1] - https://en.wikipedia.org/wiki/The_Story_of_Mel
|
| [2] -
| https://en.wikipedia.org/wiki/The_Story_of_Mel#cite_note-
| Lib...
|
| [3] - https://www.librascopememories.com/Librascope_Memorie
| s/1950_...
| xxs wrote:
| "The manual for the LGP-30 refers to "Mel Kaye of Royal
| McBee who did the bulk of the programming..." "
| userbinator wrote:
| tl;dr: DMA + bus float. I'm undecided whether this was a
| deliberate anti-emulation technique, or a clever trick to sync
| CPU execution with the DMA position. I remember seeing a similar
| type of thing in the protection of a very old PC game.
| [deleted]
| dzdt wrote:
| The Commodore 64 has a similar "feature". It has a separate 4-bit
| per address * 1k "nibble" ram chip for the screen color
| attributes. The processor and data bus are 8 bits wide. When the
| processor reads from color ram the low 4 bits come from the color
| ram chip but the hi 4 bits are disconnected. The returned results
| look a bit random but are actually whatever data was put on the
| bus the previous clock cycle.
| mananaysiempre wrote:
| Well, the OSDev Wiki's discussion of RAM detection on x86[1]
| still mentions the issue of bus capacitance in its discussion
| of memory probing (while exhorting you not to attempt memory
| probing). The text is likely old, but probably not C64 old.
| Pentium-era old maybe?
|
| [1]
| https://wiki.osdev.org/Detecting_Memory_(x86)#Practical_obst...
| and
| https://wiki.osdev.org/Detecting_Memory_(x86)#Manual_Probing...
| mijoharas wrote:
| Hyrum's law[0] seems appropriate here: With a
| sufficient number of users of an API, it does not matter
| what you promise in the contract: all observable behaviors
| of your system will be depended on by somebody.
|
| Except the API here is the behaviour of the hardware.
|
| [0] https://www.hyrumslaw.com/
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(page generated 2022-02-04 23:01 UTC)