Q:

Where can i get the cron with multitasking support

Where can i get or download free shareware cron manager which support multitasking and support php as well. so i can run php script concurrently
And 1 more. which data storage mechanism can they use to share and exchange the data. db, file, memcache, socket, or anything else

A:

You don't specify which operating system this is for. Any Linux/Unix system, including MacOS, comes with cron or cron-type software built into it. And even Windows has task scheduling capabilities, including at for one-shot jobs. In other words, you probably already have cron or cron-type software and haven't bothered looking for it in your system.
Cron by itself does not have "multitasking" capabilities. It simply starts up one or more specified programs at specified time intervals. If you want multitasking, you tell cron to start up multiple copies of the same job at the same time. 
As for sharing data, remember that each cron job is going to be a separate process/instance, and basically completely independent of any other copies of the same script. Again, you don't specify which OS you're on, so we can't tell you HOW to share data - we could point you at using a unix-domain socket on Linux, but that's pointless if you're on Windows.
So instead of complaining about getting downvoted, look at your question and realize how defficient it is, and supply the details we'd need to be able to answer you properly. Right now, we can only guess at what you want.

