In this third version of the Quote Of The Day driver, the user can write to the data that is stored in kernel memory. The pseudo device that is created in this section is a pseudo-disk device or ramdisk device. A ramdisk device simulates a disk device by allocating kernel memory that is subsequently used as data storage. See ramdisk(7D) for more information about ramdisk devices.
As in Version 2 of the Quote Of The Day driver, this Version 3 driver stores its data and makes the data available through its read(9E) entry point. This Version 3 driver overwrites characters from the beginning of the data when the user writes to the device.
This section first discusses the important code differences between this version and the previous version of the Quote Of The Day driver. This section then shows you how you can modify and display the quotation.
In addition to changes in the driver, Quote Of The Day Version 3 introduces a header file and an auxiliary program. The header file is discussed in the following section. The utility program is discussed in Using Quote Of The Day Version 3.