6 ms·

Reminds me of when I worked at a computer shop in the Pentium 1 days.. Motherboards had these complex blocks of jumpers in those days to configure the speeds, t

by _abox 5y ago

Reminds me of when I worked at a computer shop in the Pentium 1 days.. Motherboards had these complex blocks of jumpers in those days to configure the speeds, there was no autodetecting the CPU. One day I was working at a different branch filling in for someone on sick leave, and I spent an hour trying to get a PC I just built to boot reliably. Every time it crashed after an minute or so. I didn't get it, everything seemed fine. Eventually it turned out the "cheat sheet" they had of the jumpers was upside down over there. Someone had copy/pasted the pictures so it was matching the orientation of how they usually had the PC on the desk, rather than upside-down as I was used to. But the text was the right way up. So the total thing looked the same as in our branch except it wasn't. It was a square block so I hadn't noticed the orientation was different. Turned out I had the 100Mhz pentium configured for 180Mhz. Oops. That wasn't even an officially supported speed of the motherboard but the BIOS messages indicated this (which I only noticed afterwards) As we didn't want to sell this CPU after the torture I had put it through we decided to use it for a display box instead, and we tried to keep it running as long as possible by using compressed air cans upside down to blow dry ice :D It actually ran reliably until the can ran out. Only later I found out that liquid nitrogen extremeclocking was actually a thing :D

zwieback 5y ago
Great story. I remember those days well, I also remember finding every last byte of UMB, elaborate autoexec.bat files and figuring out IRQ assignments to get max functionality. Kids these days don't know how good they got it.
- necovek 5y ago
  You mean how bad they got it? :D I loved modifying CONFIG.SYS with a hex editor to translate MS-DOS 6.2 (?) boot menu.
QuercusMax 5y ago
I had a K6 233 MHz I couldn't get to run reliably in windows without underclocking to 200. But it was rock solid on Linux. Always wondered why....
- ddingus 5y ago
  I had an old Pentium 90 that would crash on NT consistently. The diagnosis was a crappy bus that resulted in various errors. Just for fun, I loaded Red Hat 5.2 on to the machine and it ran just fine. The syslog was full of bizzare errors, chattering the whole time too.
- LargoLasskhyfv 5y ago
  If something like Windows98 probably because of it not using the HLT instruction of the CPU vs. Linux doing the right thing, resulting in a cooler CPU on average when running under Linux. See http://www.benchtest.com/rain.html http://www.benchtest.com/rain.html Reasoning by MS was low quality of the countless low-end power supplies, and maybe voltage regulator modules on mainboards, being 'unreasonably' stressed by load changes that fast.
  - feisuzhu 5y ago
    I remember when I was using Windows 98, the media player [1] I was using is shipping with a tray icon which has a menu item written 'Save power when CPU is idle'[2]. It did exactly that (HLT thing). After ticking the menu, CPU just go cold. [1]: 豪杰超级解霸2000 [2]: https://www.wendangwang.com/doc/e6d559d6f2cd9ba7007939d7/3 https://www.wendangwang.com/doc/e6d559d6f2cd9ba7007939d7/3
myself248 5y ago
My 486 (nominally 40MHz) had one of those jumper blocks, and it was right near the front corner of the motherboard. Right behind the floppy-drive opening in the case, which had the drives mounted in these little removable sleds. And I didn't use my floppy drive much, and besides, the floppy cable didn't seem to mind being hot-plugged as long as you weren't accessing the disk at the time and unplugged the power connector first. So during a long download, I didn't need all 40 MHz screaming along (and heating up the chip to the point that it needed a cooling fan -- a COOLING FAN, can you imagine a CPU running so fast it couldn't cool itself on ambient air?), so I decided to see if the clock generator jumpers were hot-pluggable. Lo and behold, they were! I could reach in and seamlessly downclock the CPU to 8MHz (which was just one jumper-cap different than the 40MHz setting), which was still plenty to service the UART FIFO interrupt. Unplug the CPU fan too, which made the machine silent. Turn the monitor off, kick back in my chair, and take a catnap. The Telemate terminal software would play a little tune when a download finished, which would wake me up, I'd turn the monitor back on, open a DOS prompt, start unzipping the file, and then reach in and clock the CPU back up so the pkunzip process would finish in a timely manner. It would do 50MHz but the upper half of RAM would disappear, so there weren't a lot of workloads appropriate for that configuration....
- jon_adler 5y ago
  This sounds similar to how the 8088 XT motherboards could be toggled with a turbo button on the front of the case.
  - franga2000 5y ago
    Do I recall correctly that those turbo buttons would, counterintuitively, actually down-clock the CPU? For compatibility with software that had hard-coded timings or something?
    - ddingus 5y ago
      Yes. Old software had timing loops and other delay constructs. For a while, that button was meaningful when running games intended for the original clock rates.
zepearl 5y ago
Reading this made me remember that "Turbo button"... https://en.wikipedia.org/wiki/Turbo_button https://en.wikipedia.org/wiki/Turbo_button > With the introduction of CPUs which ran faster than the original 4.77 MHz Intel 8088 used in the IBM Personal Computer, programs which relied on the CPU's frequency for timing were executing faster than intended. Games in particular were often rendered unplayable. To provide some compatibility, the "turbo" button was added. Engaging turbo mode slows the system down to a state compatible with original 8086/8088 chips. I never had such a button in my PCs (first one was a 386SX) but I did see it on other PCs and always wondered what it did... => today I finally found that out :P
- Osiris 5y ago
  The one I had I believe was a 386. The problem was that it was easy to accidentally bump the button and my Mom would complain the computer was running slow.
  - MichaelMoser123 5y ago
    I once had a system, where the turbo button wasn't doing anything. Don't know if that was by accident, or by design.
    - zepearl 5y ago
      Right! I remember having the same experience when visiting a friend - misterious Turbo button that (apparently?) didn't have any effect :)
jart 5y ago
> As we didn't want to sell this CPU after the torture I had put it through we decided to use it for a display box instead Why? What you did is basically a burnintest. All manufacturers torture their hardware by locking it in a hot room for several days at max speed to see if it fails. The basic theory is that if it's able to survive the torture test, then it's less likely to fail once it's been sold to the customer. Parts for things like space missions go through even more severe torture tests, where they're bombarded by radiation and every horrible thing you can imagine and that actually makes the price go up!

by _abox 5y ago

zwieback 5y ago

Great story. I remember those days well, I also remember finding every last byte of UMB, elaborate autoexec.bat files and figuring out IRQ assignments to get max functionality. Kids these days don't know how good they got it.

necovek 5y ago
You mean how bad they got it? :D I loved modifying CONFIG.SYS with a hex editor to translate MS-DOS 6.2 (?) boot menu.

QuercusMax 5y ago

I had a K6 233 MHz I couldn't get to run reliably in windows without underclocking to 200. But it was rock solid on Linux. Always wondered why....

ddingus 5y ago
I had an old Pentium 90 that would crash on NT consistently. The diagnosis was a crappy bus that resulted in various errors. Just for fun, I loaded Red Hat 5.2 on to the machine and it ran just fine. The syslog was full of bizzare errors, chattering the whole time too.
LargoLasskhyfv 5y ago
If something like Windows98 probably because of it not using the HLT instruction of the CPU vs. Linux doing the right thing, resulting in a cooler CPU on average when running under Linux. See http://www.benchtest.com/rain.html http://www.benchtest.com/rain.html Reasoning by MS was low quality of the countless low-end power supplies, and maybe voltage regulator modules on mainboards, being 'unreasonably' stressed by load changes that fast.
- feisuzhu 5y ago
  I remember when I was using Windows 98, the media player [1] I was using is shipping with a tray icon which has a menu item written 'Save power when CPU is idle'[2]. It did exactly that (HLT thing). After ticking the menu, CPU just go cold. [1]: 豪杰超级解霸2000 [2]: https://www.wendangwang.com/doc/e6d559d6f2cd9ba7007939d7/3 https://www.wendangwang.com/doc/e6d559d6f2cd9ba7007939d7/3

myself248 5y ago

My 486 (nominally 40MHz) had one of those jumper blocks, and it was right near the front corner of the motherboard. Right behind the floppy-drive opening in the case, which had the drives mounted in these little removable sleds. And I didn't use my floppy drive much, and besides, the floppy cable didn't seem to mind being hot-plugged as long as you weren't accessing the disk at the time and unplugged the power connector first. So during a long download, I didn't need all 40 MHz screaming along (and heating up the chip to the point that it needed a cooling fan -- a COOLING FAN, can you imagine a CPU running so fast it couldn't cool itself on ambient air?), so I decided to see if the clock generator jumpers were hot-pluggable. Lo and behold, they were! I could reach in and seamlessly downclock the CPU to 8MHz (which was just one jumper-cap different than the 40MHz setting), which was still plenty to service the UART FIFO interrupt. Unplug the CPU fan too, which made the machine silent. Turn the monitor off, kick back in my chair, and take a catnap. The Telemate terminal software would play a little tune when a download finished, which would wake me up, I'd turn the monitor back on, open a DOS prompt, start unzipping the file, and then reach in and clock the CPU back up so the pkunzip process would finish in a timely manner. It would do 50MHz but the upper half of RAM would disappear, so there weren't a lot of workloads appropriate for that configuration....

jon_adler 5y ago
This sounds similar to how the 8088 XT motherboards could be toggled with a turbo button on the front of the case.
- franga2000 5y ago
  Do I recall correctly that those turbo buttons would, counterintuitively, actually down-clock the CPU? For compatibility with software that had hard-coded timings or something?
  - ddingus 5y ago
    Yes. Old software had timing loops and other delay constructs. For a while, that button was meaningful when running games intended for the original clock rates.

zepearl 5y ago

Reading this made me remember that "Turbo button"... https://en.wikipedia.org/wiki/Turbo_button https://en.wikipedia.org/wiki/Turbo_button > With the introduction of CPUs which ran faster than the original 4.77 MHz Intel 8088 used in the IBM Personal Computer, programs which relied on the CPU's frequency for timing were executing faster than intended. Games in particular were often rendered unplayable. To provide some compatibility, the "turbo" button was added. Engaging turbo mode slows the system down to a state compatible with original 8086/8088 chips. I never had such a button in my PCs (first one was a 386SX) but I did see it on other PCs and always wondered what it did... => today I finally found that out :P

Osiris 5y ago
The one I had I believe was a 386. The problem was that it was easy to accidentally bump the button and my Mom would complain the computer was running slow.
- MichaelMoser123 5y ago
  I once had a system, where the turbo button wasn't doing anything. Don't know if that was by accident, or by design.
  - zepearl 5y ago
    Right! I remember having the same experience when visiting a friend - misterious Turbo button that (apparently?) didn't have any effect :)

jart 5y ago

> As we didn't want to sell this CPU after the torture I had put it through we decided to use it for a display box instead Why? What you did is basically a burnintest. All manufacturers torture their hardware by locking it in a hot room for several days at max speed to see if it fails. The basic theory is that if it's able to survive the torture test, then it's less likely to fail once it's been sold to the customer. Parts for things like space missions go through even more severe torture tests, where they're bombarded by radiation and every horrible thing you can imagine and that actually makes the price go up!