2.4 I/O Status Block

Figure 2-5 shows the I/O status block (IOSB) for all disk device QIO functions except sense mode. Figure 2-6 shows the I/O status block for the sense mode function. Figure 2-6 lists the status messages for all functions and devices. (The OpenVMS system messages documentation provides explanations and suggested user actions for these messages.)

Figure 2-5 IOSB Contents

The byte count is a 32-bit integer that gives the actual number of bytes transferred to or from the process buffer.

Figure 2-6 IOSB Contents for the Sense Mode Function

The second longword of the I/O status block for the sense mode function returns information about the cylinder, track, and sector configurations for the particular device.