Journaling - any benefits for a MacBook?
in [Mac Systems]
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From: Kevin McMurtrie on 31 May 2010 22:53 In article <isw-2D306D.10433731052010@[216.168.3.50]>, isw <isw(a)witzend.com> wrote: > In article <4c036576$0$22127$742ec2ed(a)news.sonic.net>, > Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote: > > > In article <300520100806057875%aeiou(a)mostly.invalid>, > > Mark Conrad <aeiou(a)mostly.invalid> wrote: > > > > > I have been leaving journaling turned off for ages > > > on my MacBook Pro, with nothing bad happening. > > > > > > Is journaling just a placebo? > > > > > > Mark- > > > > It assists with recovery from panics and loss of power. I only > > recommend it for 10.6 or later. I've seen it mask volume corruption in > > 10.5 and earlier that lead to the eventual loss of files. > > Interesting. How would one go about discovering whether "masked > corruption" exists or not? And what could be done about it if it does? > > Isaac Turning on journalling disables automatic volume verification and repair. In theory, it should be needed any more. In reality, it was still needed in 10.5. I had four computers that regularly suffered from volume corruption. If I didn't catch it soon enough with Disk Utility I'd start losing files. I haven't seen disk corruption in 10.6 yet. Some major software updates from Apple still force a volume check and repair regardless of journaling, just to make sure that the update doesn't get scrambled. -- I won't see Google Groups replies because I must filter them as spam
From: Kevin McMurtrie on 31 May 2010 23:09 In article <310520101727292379%aeiou(a)mostly.invalid>, Mark Conrad <aeiou(a)mostly.invalid> wrote: > In article <310520100943555145%nospam(a)nospam.invalid>, nospam > <nospam(a)nospam.invalid> wrote: > > > > I will be glad when "real" 64 bit operation becomes > > > commonplace on Macs, so that developers will > > > actually write programs that can utilize 64 bit capability. > > > > that happened several years ago. > > Yes, with portions of OS X "system files" and even their > associated buses, caches, buffers. That did little good > "years ago" because there were no app's around to take > advantage of the 64-bit system files. > > > > > currently, there are plenty of 64 bit apps available, including > > adobe photoshop cs5, lightroom, and even apple's chess game. > > Yes indeed, there must be all of 1% of 64-bit app's around. <g> > > That hardly constitutes what most people think of when we > use the word "plenty". > > That said, even the Windows guys are very lean on 64-bit app's, > despite their jumping up and down and raving about it. > > They even have 64-bit usenet newsgroups for Windows guys, > to create the superficial impression they are somehow ahead of > the backward Mac people. ;-) > > A few app's, such as the "64-bit compatible Dragon medical" app' > can actually be run on a 64-bit Windows OS, but like "Jolly Roger" > posted in a recent post to me here, that does not mean the > 64-bit version of Dragon will run twice as fast on the 64-bit OS. > > Actually, users found that running Dragon on a 64-bit OS yielded > only very minor increases in speed, hardly noticable. > > In order to run twice as fast, Dragon code would have to be > completely re-written for 64-bit use, a job that could take years. > > Not only that, but new CPUs would need to be created by Intel, > to take full advantage of 64-bit capabilities. > > Even on my most recent 17" MacBook Pro with all the bells and > whistles, there is limited 64-bit capability. For example, it does > not even have a 64-bit Kernel or Extensions. > > I have 8 GB of RAM, sure, but I can only access 4 GB of Ram > at a time. I need to access the CPU two separate times in order > to use the full 8 GB of RAM that I have, which takes added time. > > A true 64-bit Kernel could access all 8 GB of RAM at once. > > All in all, I do not look for true 64-bit operation for at least > another decade or two. > > Mark- There are two advantages to 64 bit software: 1) A few of the limitations of the archaic x86 CPU have been improved. Most importantly, there are more CPU registers. Operations that perform complex math can get a significant speed boost. Simple operations see no benefit. (If MacOS X still supported Power CPUs, there'd be no improvement because it is already a modern CPU.) 2) Access to very large amounts of data becomes simpler. In 32 bit mode, access to large data sets must be performed as file access. In 64 bit mode, it can be performed as memory access. This reduces the complexity in some kinds of new software, which should hopefully make it more robust and more efficient. -- I won't see Google Groups replies because I must filter them as spam
From: Kevin McMurtrie on 31 May 2010 23:14 Wear leveling is where disk writes are re-mapped constantly in the SSD. It doesn't matter if the OS writes to the same logical address non-stop. The disk isn't bricked until the write cycles are burned up on all the cells and the spares. -- I won't see Google Groups replies because I must filter them as spam
From: nospam on 31 May 2010 23:18 In article <4c04760e$0$22144$742ec2ed(a)news.sonic.net>, Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote: > Turning on journalling disables automatic volume verification and > repair. no it doesn't. > In theory, it should be needed any more. In reality, it was > still needed in 10.5. I had four computers that regularly suffered from > volume corruption. If I didn't catch it soon enough with Disk Utility > I'd start losing files. something else was wrong, not journaling.
From: Kevin McMurtrie on 1 Jun 2010 02:43
In article <310520102018098423%nospam(a)nospam.invalid>, nospam <nospam(a)nospam.invalid> wrote: > In article <4c04760e$0$22144$742ec2ed(a)news.sonic.net>, Kevin McMurtrie > <mcmurtrie(a)pixelmemory.us> wrote: > > > Turning on journalling disables automatic volume verification and > > repair. > > no it doesn't. Read the man page for fsck_hfs if you'd like. Booting and disk mounting don't use the '-f' option. > > > In theory, it should be needed any more. In reality, it was > > still needed in 10.5. I had four computers that regularly suffered from > > volume corruption. If I didn't catch it soon enough with Disk Utility > > I'd start losing files. > > something else was wrong, not journaling. Of course, but that something else was unknown and Apple isn't one to admit bugs. Turning off journaling has a side effect of enabling automatic volume verification, and that helped fix the corruption. -- I won't see Google Groups replies because I must filter them as spam |