6 ms·

How bad is that? If I'm actively using one program, and that program is waiting on a page from disk, what useful thing can you do in the meantime?

by marvy 9y ago

kstrauser 9y ago
IIRC, OS 7 was only cooperatively multitasked. If that were the case, and the program was blocked by the VMM so that it couldn't release the CPU to the next program, I'd imagine the whole system would hang until the read was finished. I worked with a web developer in the mid 90's who served some image files off his desktop Mac. We noticed intermittent hangs and slowdowns during file transfers. After much head scratching, we pieced together that every time he held down his mouse button, networking stopped until he let go. This was 100% reproducible, and 100% hilarious to us Linux folks. It got eventually got better.
- derefr 9y ago
  Try telling iTunes to download a large number of files from iTunes in the Cloud, and then popping open the little downloads popover and continuously scrolling it up and down. Still as of iTunes 12.x, the downloads would fail to progress! (Not just, like, the UI failing to update; the download tasks themselves would fail to read(2) from their sockets, and so the TCP streams would get blocked, causing the server to stop sending.) I think this is a rather uniquely-bad behavior among modern macOS apps, though; I have a feeling it's because it's the only one that also runs on Windows, and the required portability layer is "a bit" legacy.
  - deleted 9y ago
    [deleted]
- mrpippy 9y ago
  Yep, if you held down the menu bar no other applications would get any time or events except for interrupt-time callbacks like VBL tasks and async IO completion routines. Any application that actually did something on classic MacOS while the menu bar was held down was doing it through those (tricky to get right) mechanisms.
  - kalleboo 9y ago
    I remember installing an INIT called "Menutasking enabler" that let processes continue in the background. The downside was that any app that redrew a window would end up drawing all over the open menu.
- taeric 9y ago
  I was just remembering that you could basically "freeze" those machines by holding down the mouse button. I can't tell if I'm vindicated in my memory, or horrified that that was how things worked. Possibly both.
  - astrodust 9y ago
    It was roughly like that. Windows versions prior to 95 also worked on the same principle (1.0 to 3.11). That was why when BeOS came out around that time and, often on the same hardware you used MacOS 7 on, you could drag windows around with video playing in them, with 3D objects spinning in other window, with video being wrapped on to 3D objects in real-time, it was utterly mind-blowing. The user interface never quit on you, it never beachballed, it just kept going. I have to chuckle when I see Windows 10 struggle to do what BeOS did effortlessly on a 603e machine with a video card so primitive it couldn't even run any real 3D games.
    - davidgay 9y ago
      This is where some of us mention "Amiga", then duck ;) Same difference, but 10 years prior to BeOS...
      - astrodust 9y ago
        The Amiga was the first consumer OS with pre-emptive multi-tasking, absolutely, but BeOS was the first with such aggressive multi-threading and exceptional support for multiple CPUs. On BeOS the menu UI had its own thread. Even if the app was busy thinking it still wouldn't jam. That wasn't the case on other operating systems that simply had multi-process support.
- wtallis 9y ago
  > After much head scratching, we pieced together that every time he held down his mouse button, networking stopped until he let go. This was back when holding the mouse button down was required to keep a menu open, right?
  - kstrauser 9y ago
    That's correct. So as he wove his way through Photoshop, our downloads would sputter and stall.
- einr 9y ago
  Sounds like this web developer's computer may have been one of the infamous Performa/Power Macintosh x200 series[1]. These are ridiculously designed machines. Choice quote from http://lowendmac.com/1997/performa-and-power-mac-x200-issues/ http://lowendmac.com/1997/performa-and-power-mac-x200-issues...: One of the biggest complaints about the x200 series is slow Internet handling. For one thing, looking at the chart above, all data from either the ports or the ethernet controller must pass through the processor to get to memory, then be processed, sent to the IDE controller for cache saving, and then interpreted for graphics display. There are symptoms to notice because of this. While a web page is loading, typed characters will be lost. When dealing with high IDE access, the graphics controller will seem to freeze. When copying to a network or downloading a file, the monitor will rarely update and will have redraw problems. Spooled print jobs will take forever if lots of processor resizing is necessary. [1] http://lowendmac.com/2014/power-mac-and-performa-x200-road-apples/ http://lowendmac.com/2014/power-mac-and-performa-x200-road-a...
  - kalleboo 9y ago
    When I was a kid we had a Performa 5200, and I suffered from this. We also got a surplus Quadra 800 with a 66 MHz PowerPC upgrade from my dad's work - which outperformed the 75 MHz Performa in everything aside from MP3 decoding. We also ran into the serial port issues the article describes, we got better performance hooking our 56k modem up to the Quadra and sharing that connection to the 5200 over LocalTalk via IPNetRouter than actually using the modem directly.
    - Angostura 9y ago
      Didn't the Performa use the PPC 603? ISTR it did. The 603 was the 'cheap-n-cheerful' chip in the family, I suspect the Quadra upgrade would have had a 601 or 604, both of which had more oomph.
      - kalleboo 9y ago
        Yeah doing the research now - the 5200 had a 603 @ 75 MHz, and the PowerMac PDS Card had a 601 @ 66 MHz. I was also reminded the 603 had too small of a L1 cache to hold the the 68K emulator, reducing performance even further... Now I'm curious what made the 5200 better at MP3 playback. My recollection is that the only way to get the upgraded Quadra to play MP3s in realtime was with SoundApp monopolizing the CPU so you couldn't even click anything else. On the Performa, you could run MacAmp in the background while browsing the web, with stuttering "only" during whole page repaints. This was 20 years ago, my recollection could be poor... I soon got my own Quadra 660AV (video digitizing!) and eventually a PowerMac 7500 (that I upgraded to G3 and could even run early versions of OS X with Xpostfacto)
- floatboth 9y ago
  Yeah, everything pre OS X was cooperative, including the last one (9.2.2).

How bad is that? If I'm actively using one program, and that program is waiting on a page from disk, what useful thing can you do in the meantime?

by marvy 9y ago

How bad is that? If I'm actively using one program, and that program is waiting on a page from disk, what useful thing can you do in the meantime?

kstrauser 9y ago

IIRC, OS 7 was only cooperatively multitasked. If that were the case, and the program was blocked by the VMM so that it couldn't release the CPU to the next program, I'd imagine the whole system would hang until the read was finished. I worked with a web developer in the mid 90's who served some image files off his desktop Mac. We noticed intermittent hangs and slowdowns during file transfers. After much head scratching, we pieced together that every time he held down his mouse button, networking stopped until he let go. This was 100% reproducible, and 100% hilarious to us Linux folks. It got eventually got better.

derefr 9y ago
Try telling iTunes to download a large number of files from iTunes in the Cloud, and then popping open the little downloads popover and continuously scrolling it up and down. Still as of iTunes 12.x, the downloads would fail to progress! (Not just, like, the UI failing to update; the download tasks themselves would fail to read(2) from their sockets, and so the TCP streams would get blocked, causing the server to stop sending.) I think this is a rather uniquely-bad behavior among modern macOS apps, though; I have a feeling it's because it's the only one that also runs on Windows, and the required portability layer is "a bit" legacy.
- deleted 9y ago
  [deleted]
mrpippy 9y ago
Yep, if you held down the menu bar no other applications would get any time or events except for interrupt-time callbacks like VBL tasks and async IO completion routines. Any application that actually did something on classic MacOS while the menu bar was held down was doing it through those (tricky to get right) mechanisms.
- kalleboo 9y ago
  I remember installing an INIT called "Menutasking enabler" that let processes continue in the background. The downside was that any app that redrew a window would end up drawing all over the open menu.
taeric 9y ago
I was just remembering that you could basically "freeze" those machines by holding down the mouse button. I can't tell if I'm vindicated in my memory, or horrified that that was how things worked. Possibly both.
- astrodust 9y ago
  It was roughly like that. Windows versions prior to 95 also worked on the same principle (1.0 to 3.11). That was why when BeOS came out around that time and, often on the same hardware you used MacOS 7 on, you could drag windows around with video playing in them, with 3D objects spinning in other window, with video being wrapped on to 3D objects in real-time, it was utterly mind-blowing. The user interface never quit on you, it never beachballed, it just kept going. I have to chuckle when I see Windows 10 struggle to do what BeOS did effortlessly on a 603e machine with a video card so primitive it couldn't even run any real 3D games.
  - davidgay 9y ago
    This is where some of us mention "Amiga", then duck ;) Same difference, but 10 years prior to BeOS...
    - astrodust 9y ago
      The Amiga was the first consumer OS with pre-emptive multi-tasking, absolutely, but BeOS was the first with such aggressive multi-threading and exceptional support for multiple CPUs. On BeOS the menu UI had its own thread. Even if the app was busy thinking it still wouldn't jam. That wasn't the case on other operating systems that simply had multi-process support.
wtallis 9y ago
> After much head scratching, we pieced together that every time he held down his mouse button, networking stopped until he let go. This was back when holding the mouse button down was required to keep a menu open, right?
- kstrauser 9y ago
  That's correct. So as he wove his way through Photoshop, our downloads would sputter and stall.
einr 9y ago
Sounds like this web developer's computer may have been one of the infamous Performa/Power Macintosh x200 series[1]. These are ridiculously designed machines. Choice quote from http://lowendmac.com/1997/performa-and-power-mac-x200-issues/ http://lowendmac.com/1997/performa-and-power-mac-x200-issues...: One of the biggest complaints about the x200 series is slow Internet handling. For one thing, looking at the chart above, all data from either the ports or the ethernet controller must pass through the processor to get to memory, then be processed, sent to the IDE controller for cache saving, and then interpreted for graphics display. There are symptoms to notice because of this. While a web page is loading, typed characters will be lost. When dealing with high IDE access, the graphics controller will seem to freeze. When copying to a network or downloading a file, the monitor will rarely update and will have redraw problems. Spooled print jobs will take forever if lots of processor resizing is necessary. [1] http://lowendmac.com/2014/power-mac-and-performa-x200-road-apples/ http://lowendmac.com/2014/power-mac-and-performa-x200-road-a...
- kalleboo 9y ago
  When I was a kid we had a Performa 5200, and I suffered from this. We also got a surplus Quadra 800 with a 66 MHz PowerPC upgrade from my dad's work - which outperformed the 75 MHz Performa in everything aside from MP3 decoding. We also ran into the serial port issues the article describes, we got better performance hooking our 56k modem up to the Quadra and sharing that connection to the 5200 over LocalTalk via IPNetRouter than actually using the modem directly.
  - Angostura 9y ago
    Didn't the Performa use the PPC 603? ISTR it did. The 603 was the 'cheap-n-cheerful' chip in the family, I suspect the Quadra upgrade would have had a 601 or 604, both of which had more oomph.
    - kalleboo 9y ago
      Yeah doing the research now - the 5200 had a 603 @ 75 MHz, and the PowerMac PDS Card had a 601 @ 66 MHz. I was also reminded the 603 had too small of a L1 cache to hold the the 68K emulator, reducing performance even further... Now I'm curious what made the 5200 better at MP3 playback. My recollection is that the only way to get the upgraded Quadra to play MP3s in realtime was with SoundApp monopolizing the CPU so you couldn't even click anything else. On the Performa, you could run MacAmp in the background while browsing the web, with stuttering "only" during whole page repaints. This was 20 years ago, my recollection could be poor... I soon got my own Quadra 660AV (video digitizing!) and eventually a PowerMac 7500 (that I upgraded to G3 and could even run early versions of OS X with Xpostfacto)
floatboth 9y ago
Yeah, everything pre OS X was cooperative, including the last one (9.2.2).