Standard Microsystems Inc, Hauppauge, New York, has applied the technique of semi-custom chip design to squeeze the 40 or so integrated circuits in a typical hard disk controller into a single package that can be tailored for many different configurations. The chip, set for beta testing in July, will be made using six standard design blocks, all of which can be customised. The six are a host interface, disk interface, error checking logic, DMA controller, local microprocessor interface and a RAM-based microsequencer. Each block is a standard module in the company’s design library which engineers will use to build custom circuits for hard disk interfaces. Using standard modules will considerably speed up design time for hard disk controllers, the company claims. Although the modules are standard, each can be customised, so that the designer can choose between a synchronous SCSI or asynchronous SCSI interface and from three different data encoding schemes – NRZ, MFM or RLL – in creating the chip. The system is being extended to support optical as well as magnetic drives.