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Hi,<br />
<br />
With Storport driver, &nbsp;the routine HWBuildIO is called &nbsp;wihtout synchronization i.e. without taking any locks. Hence this routine gets invoked paralelly for multiple commands. <br />
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However the routine HWStartIO is only called asynchronously. I.e. A spin lock is acquired by storport before calling this routine and is it released only after completing the execution of this routine. I understood from an article that this is done to avoid the interrupts taking the control away from this routine while this routine is executing. <br />
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My question is why it is important not to allow the control to be preempted by the ISR while the HWStartIO is executing? What consequences it will have to allow the control to be preempted in the middle of StartIO? Can i get a practical example anywhere?
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Hi,

With Storport driver,  the routine HWBuildIO is called  wihtout synchronization i.e. without taking any locks. Hence this routine gets invoked paralelly for multiple commands. 

However the routine HWStartIO is only called asynchronously. I.e. A spin lock is acquired by storport before calling this routine and is it released only after completing the execution of this routine. I understood from an article that this is done to avoid the interrupts taking the control away from this routine while this routine is executing. 

My question is why it is important not to allow the control to be preempted by the ISR while the HWStartIO is executing? What consequences it will have to allow the control to be preempted in the middle of StartIO? Can i get a practical example anywhere?

Why HWStartIO method is called synchronously?

The Microsoft Legacy Operating System topic includes legacy versions of Microsoft operating systems prior to Windows 2000: All versions of MS-DOS and other versions developed for specific manufacturers and Windows 3/3.1, Windows 95 and Windows 98, plus any other Windows-related versions, and Windows Mobile.

Microsoft Legacy OS

Servers are computing devices that are similar to desktop computers in that they have the same basic components, but are significantly different in size, configuration and purpose. Servers are usually accessed over a network, and many run unattended, without a computer monitor, input device, audio hardware or USB interfaces. Many servers do not have a graphical user interface (GUI), and are configured and managed remotely. Servers typically include hardware redundancy such as dual power supplies, RAID disk systems, and ECC memory, along with extensive pre-boot memory testing and verification. Critical components might be hot swappable, and to guard against overheating, servers might have more powerful fans or use water cooling.