difference between "buffer" and "cache"

Hi everyone.
I looked in the Geektionary, and didn't find definitions for "buffer" and "cache".

I could google about (I usually do), but tonight I thought I'd be lazy and just ask the crew.

So how 'bout it?

Is cache just the L1 and L2 for the processor?

Is buffer just to make up the difference in transfer speed to hdd or cdrom?

Or is there something else to it?

Thank you,
Robert
Your GRATEFUL student

 

I think buffer is the same as cache but cache is faster .....I think....

 

Thank you, ACE.
Well, if ACE is not completely sure, then lets look in to this more deeply...

Others may step in to clear it up...

 

Oh, and I want to "show off" by showing everyone how I can redirect the output
of a command to a file, then open it with a text editor, then copy and paste it
to the message board. Here goes:

total used free shared buffers cached
Mem: 515380 500328 15052 0 21416 296964
-/+ buffers/cache: 181948 333432
Swap: 1261020 40 1260980

 

Ok heres all i could find in a quick search on MG its 2:30 AM here im ganna passout ill look a bit more tomarrow....................here we go.........


cache n 1: a hidden storage space (for money or provisions or weapons) 2: a secret store of valuables or money [syn: hoard, stash] 3: (computer science) RAM memory that is set aside as a specialized buffer storage that is continually updated; used to optimize data transfers between system elements with different characteristics [syn: memory cache] v : save up as for future use [syn: hoard, stash, lay away, hive up, squirrel away]

 

Now I feel like a lowlife for being so lazy to not do a google myself, LOL.
Have a good night, Ace, I'll check out the links...

 

Yes, I will look more. Interesting, though, one of those pages had them as asynonyms:

Quote:

memory cache
n : (computer science) RAM memory that is set aside as a
specialized buffer storage that is continually updated;
used to optimize data transfers between system elements
with different characteristics [syn: cache]

LOL.

 

Cache & buffers are both ram, but serve different functions. Cache (L1, L2...) is general purpose storage where the cpu can park any kind of data it's using, normally located as a large block to the side of the processing area. Buffers are small dedicated storage areas in the processing areas of the chip itself where very specific small chunks of data are stored during procecessing. Buffers are frequently used to store instructions temporaily that need to be used multiple times on the data being manipulated, rather than hitting cache or main memory every time that instruction is needed.

Since this is in the Software forum, software buffers are defined areas in a program where data is written, generally with defined limits as to how MUCH data can be written. Microsoft has a hard time setting limits, hence the frequent bug fixes to cure buffer overuns, where too much data done just the right way can crash or cripple the program.

 

One can never get enough definitions

A buffer is just a piece of memory to store data.

If there is logic around the buffer, which makes sure that the data placed in the buffer(Ex. in RAM) is an image of some data placed elsewhere(Ex. on Harddisk), then the whole thing (buffer+logic) is a cache.

The idea about the cache is to place the data closer to the processing, so the access is faster.

Many times it is possible to increase the buffer used for caching, so it is able to have a large amount of data available for fast access on the expense of memory(RAM).

 

Well, from my understanding cached is PROCESSED data which can be accessed easily. For example, MajorGeeks uses index caching on the main website, where the CMS (content management system) writes the current index of a catagory to a HTML file (which some people will have noticed.... majorgeeks.com/downloads2.*html*) so that less load is put on the server continuiously dragging a great big table out of the DB every time. Serving HTML requires much less processing power than running the php engine, and accessing the database, thus keeping loads low as possible, giving everyone a speedy website. The cache will be updated either using a chron job or a script that either the admin or a use accessing a certain index at a certain time. Phillip should know more about this than I, since he wrote it

Also, from my experience a buffer is an output of data which is about to be processed again. Like a media file playing over the net. The file is stored in a buffer, untill it is processed a second time when it is played.

Anyway, thats probably completley wrong but thats just how ive used both of them