RAM disk in OSX
- Thread starter twitchg3
- Start date
I was thinking about that swap partition deal but I dont know anything about that. The ONLY things I know about RAM disks are that in OS 9, it was simple through the Memory control panel. And then anything on that RAM disk was very fast. That would be nice to set up like a 200mb RAM Disk and install some programs on that. Imagine installing OSX on a RAM Disk =) That would be tight.
swap partitions are easy to set up and greatly improve performance. however, a swap partition is exaclty the opposite of a ram disk. swap partition is a disk used as memory, where as ram disk is memory chips used as a disk, complete with a file system..
as i understand it, ram disk for OSX is not yet implemented. read this thread from macnn.com:
http://forums.macnn.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=46&t=001454
as i understand it, ram disk for OSX is not yet implemented. read this thread from macnn.com:
http://forums.macnn.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=46&t=001454
swap disk = slow memory for your system
ram disk = fast disk space
you can easily spare lots of swap space from your drive, if you have several gigs, and it can greatly help your system to have your swap disk seperated from the rest of your disk by making a seperate partition. it improves performance of your system greatly. and it is a cheap price.
ram disk is much more expensive. you don t get much storage space, ram space is much much more expensive than disk space, and every meg of ram that you use for disk space costs you RAM you could use for memory which will slow your system. but if you have lots of ram to spare, and you can afford it, then you get a disk that is extremely extremely fast. for things like web caching, it can be really effective, if you can spare the ram. a lot of people really like this feature.
according to the darwin developer who posted on the thread i put up before, implementing an efficient ram disk is extremely difficult. so you hear it from the horses mouth. RAM disk is not available in OSX. i personally believe that apple will want to offer us at least every feature for OSX that was available for OS9, so i think it will come out eventually for OSX, though i don t think it will be soon. i don t personally have a use for RAM disk, ut it sounds cool, and i can imagine that when i need it, it will come in great use.
let s be patient, shall we?
ram disk = fast disk space
you can easily spare lots of swap space from your drive, if you have several gigs, and it can greatly help your system to have your swap disk seperated from the rest of your disk by making a seperate partition. it improves performance of your system greatly. and it is a cheap price.
ram disk is much more expensive. you don t get much storage space, ram space is much much more expensive than disk space, and every meg of ram that you use for disk space costs you RAM you could use for memory which will slow your system. but if you have lots of ram to spare, and you can afford it, then you get a disk that is extremely extremely fast. for things like web caching, it can be really effective, if you can spare the ram. a lot of people really like this feature.
according to the darwin developer who posted on the thread i put up before, implementing an efficient ram disk is extremely difficult. so you hear it from the horses mouth. RAM disk is not available in OSX. i personally believe that apple will want to offer us at least every feature for OSX that was available for OS9, so i think it will come out eventually for OSX, though i don t think it will be soon. i don t personally have a use for RAM disk, ut it sounds cool, and i can imagine that when i need it, it will come in great use.
let s be patient, shall we?
Krevinek
Evil PPC Tweaker
I will both applaud Apple and scratch my head in wonder if a RAM disk feature is added to OS X. In OS 9, since everything was statically partitioned, and you could turn off VM, you had control enough for a properly implemented RAM disk.
However, in OS X you don't have the fine control. Two simple RAM disk implementations for OS X are the following: either just allocate a large hunk of RAM and use it as a disk, or hardwire a set amount of RAM for the disk. Either one has large issues. The first one can get swapped out to disk, slowing it down and negating the speed boost. The second can possibly cause RAM fragmentation is it isn't allocated at boot (very bad), and essentially lock away that RAM, and doing as another poster said: slowing down your system since more stuff is getting swapped out to disk.
However, in OS X you don't have the fine control. Two simple RAM disk implementations for OS X are the following: either just allocate a large hunk of RAM and use it as a disk, or hardwire a set amount of RAM for the disk. Either one has large issues. The first one can get swapped out to disk, slowing it down and negating the speed boost. The second can possibly cause RAM fragmentation is it isn't allocated at boot (very bad), and essentially lock away that RAM, and doing as another poster said: slowing down your system since more stuff is getting swapped out to disk.
rharder
Do not read this sign.
I too would like to see a dedicated RAM Disk capability, but in the mean time, don't forget that OS X does a dandy job of caching disk read/writes on its own. A number of times I've been manipulating large files, and the first pass through is slow, but future passes are much faster at reading the data. Pretty nifty.
-Rob
-Rob
Yea, OSX does a good job at caching things. Slow at first and fast after. Like opening applications: many bounces, then 2nd time and after less bounces. But, imagine installing OSX on a RAM disk and using that as a boot disk! Or imagine installing Photoshop on a RAM disk. That would be very very cool.. and fast. I hope apple gets it working soon.
Krevinek
Evil PPC Tweaker
You wouldn't be able to install OS X on a RAM disk, because OS X would have to be already running to manage the RAM disk... catch-22.
You do realize that by running Photoshop on a RAM disk, it lowers the amount of available RAM available for Photoshop and causes it to access the disk more often for it's RAM usage? Nearly negates (if it doesn't fully negate) the benefits of doing so. Photoshop is a RAM beast, and I would bet you need the full 1.5GB to prevent Photoshop from swapping out to disk and ruining the boost given to it from the RAM disk.
You do realize that by running Photoshop on a RAM disk, it lowers the amount of available RAM available for Photoshop and causes it to access the disk more often for it's RAM usage? Nearly negates (if it doesn't fully negate) the benefits of doing so. Photoshop is a RAM beast, and I would bet you need the full 1.5GB to prevent Photoshop from swapping out to disk and ruining the boost given to it from the RAM disk.