Compaq Computer Corp is ready to go with the 120Mb 3.5 floppy disk drive it commissioned last year. According to US PC Week, in the middle of next month, Compaq will add 150MHz and 166MHz Pentium-based ProLinea and Deskpro systems with the floppy disk unit, and also a keyboard with a built-in scanner, and an erasable optical drive that also reads CD-ROM disks. Compaq commissioned Minnesota Mining & Manufacturing Co to do the disks, and Quantum Corp’s manufacturing partner Matsushita-Kotobuki Electronics Industries Ltd to do drives, which read current 1.44Mb disks (CI No 2,660). The drive is expected to cost $200. The erasable phase-dual compact disk drive takes both standard CD-ROMs and 650Mb erasable optical platters for archiving, using the same heads to read both types of disk. It is expected to go for $600 as an add-on.