dale (05/27/82)
Douglas Price is incorrect in some of his assertions regarding UNIX. The best way to implement a database mgmt. capability in UNIX is NOT to build it on top of the UNIX filesystem, but to build it using a "raw" character device portion of a disk. This gives complete control over the order of the writes and reads with DMA directly to user space. The systems we build at BTL Columbus all use such a mechanism. Some of the systems have a special driver in the kernel to allocate and deallocate sections of this device, others are implemented entirely in user space. Doug's comments about pipes are also wrong. For some time now fstat has returned info describing how much is in a pipe. And it is certainly possible to use alarm() to time out of a pipe read. Hence the read CAN be aborted.
dale (05/27/82)
I forgot to sign my name to my followup to Douglas Price's article. Sorry. Dale DeJager BTL Columbus cbosg!dale