On Thu, 22 Jan 2015, William H. Magill wrote: > After a tremendous amount of effort on the part of numerous kernel > programmers at DEC, they discovered that the bottom level BSD I/O > modules had not been "looked at" (literally) since PDP days. Disk I/O > was being done in 128 byte blocks.
You sure abut this? My memory of the PDP days (ye olde 11/40) was that I/O was the same as the disk sector i.e. 512 bytes; this was V5/V6/V7 Unix. > One thing which I noticed immediately when I turned on iCloud disk in > Yosemite -- the "lag" involved with launching any program which stored > anything "in the cloud." Not unexpected, but significant none the less. I've never bothered with iCloud; I don't store much stuff anyway (see my signature), and it all gets backed up to my Time Capsule. > Similarly, I had a problem where my internal hard drive would literally > not spin-up. Took the iMac in to the Apple Store and they ran their > diagnostics and pronounced nothing wrong -- the tests passed with flying > colors! > > I finally convinced them that the drive was not spinning up and they got > a tech to come out front who had a stethoscope and instantly verified > that the drive was not spinning. Didn't they see the dreaded question mark on booting up? > I've seen too many cases related to both BSD (and later Mach, i.e. NeXT > and OSX) where much of the hardware level "stuff" is completely ignored > by any of the upper-level reporting software. -- one of the main reasons > why Drive manufacturers developed S.M.A.R.T. -- the OS does not do the > job. Hmmm... I just tried SMART on my drive, but being an external USB drive (long story) it's not supported, so... > In my experience, by the time the OS flags a Disk error, you have been > suffering constant performance degrading failures which are simply below > the "reporting threshold", for quite some time. I have been seeing slow performance lately; I bought the MacBook early in 2010, but it's a late 2009 model. I wonder? -- Dave Horsfall DTM (VK2KFU) "Bliss is a MacBook with a FreeBSD server." http://www.horsfall.org/spam.html (and check the home page whilst you're there) _______________________________________________ macports-users mailing list [email protected] https://lists.macosforge.org/mailman/listinfo/macports-users
