QEMU is a powerful emulator, which means that it can emulate a variety of processor types. Xen uses QEMU for HVM guests, more specifically for the HVM guest's device model. The Xen-specific QEMU is called qemu-dm (short for QEMU device model) QEMU uses emulation; KVM uses processor extensions (intel-VT) for virtualization. Both Xen and KVM merge their various functionality to upstream QEMU, that way upstream QEMU can be used directly to accomplish Xen device model emulation, etc. Xen is unique in that it has paravirtualized guests that don't require hardware virtualization. Both Xen and KVM have paravirtualized device drivers that can run on top of the HVM guests. The QEMU hypervisor is very similar to the KVM hypervisor. Both are controlled through libvirt, both support the same feature set, and all virtual machine images that are compatible with KVM are also compatible with QEMU. The main difference is that QEMU does not support native virtualization. Consequently, QEMU has ...
I have faced this issue in Joomla site and searched the forums but none of the forums including joomla did not give solution for me. They simply suggest to check joomla version, php version compatibility and php extensions. Finally I have fixed the issue. Issue:- --------- [26-Sep-2014 18:11:29 Europe/Berlin] PHP Fatal error: Class 'JFactory' not found in /home/test/public_html/index.php on line 31 Cause & Solution:- ----------------------- In my case, it seems file which gives the class JFactory was missed. /home/test/public_html/libraries/joomla/factory.php --->Core file for Joomla. Simply restore that file under proper path to fix the issue.
Question : How push notification works for FCM/Apple push (APNs) in network level? There are so many articles describes the push notification work flow in application level. But how APN servers sends the notifications to clients in network level are not explained in many articles. The answer is long polling connections from client devices(Mobiles, Laptops) to APN servers. why long polling connection? if its short connections then it leads to notification delays based on polling interval. APN servers are configured with long keepalive timeout(usually this timeout is very short around 60 secs to 300 secs in normal application servers) so push notifications will deliver to client devices immediately through same long lived TCP connection once APN receives the notification from app server side why polling comes here? TCP connection always disconnects if there is no internet or network change or device restarts, etc,… In this case, client device always keep trying/polling to the AP...
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