If you enable the columns I/O Read Bytes and I/O Write Bytes in Task Manager (Processes) tab, I see jqs.exe reading Gigabytes during the course of the day.
I'm hardly running any Java apps.
I this correct ? How does JQS work ?
JQS reads the files needed at java-startup again and again, so that the OS keeps them cached.
Don't worry about the high amount of I/O, its all buffered/cached so its very cheap and fast - and should not slow down your system (except for the amount of RAM used to cache the files).
JQS Read Bytes is growing even when I do not run any Java apps !
The service wakes up from time to time and touches some files on the disk so that the OS bring them back into the file cache (keeps them warm) so that next time you use java it starts up quickly.
Note that if you're running low on memory (or of there's some other activity on the system), the os purges the caches, so you're not wasting memory.
Please forgive me if I sound frustrated; I do like things that use smart methods to go faster.
But I don't like a process that takes more resources than the speedup is worth. It sounds like JQS speeds up my once-a-month java usage, but in turn it requires the following:
-- Reduced cache: I want cache so that my most recently used things will start faster, and I want that more than I want Java to start faster. That's why I paid for a CPU with bigger cache. But it sounds like JQS puts itself into the cache, replacing whatever I put there
-- More wear on my hard drive, since it seems to spin to allow file refresh, to keep the cache warm
-- More power consumption in general (I know, not much on my PC, but it would be a fun back-of-the-envelope calculation to see how much power is used by JQS which is installed in 90% of all computers world-wide
-- A tiny slow-down on my already slow older PCs
You may say, "Quit complaining -- just disable it in the Control Panel --> Java --> Advanced tab." I do. Then two months later, I do again, after yet another Java update... on all my PCs & laptops... and then again....
I wish JQS were an opt-in feature, chosen during installation.
But if I can't persuade that to happen, at least it should keep my settings when Java updates! (Please...!)
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