trb@masscomp.UUCP (03/12/84)
The idiot in me insists that I continue to feed the flames: How can I resist responding to a personal affront? William LeFebvre at Rice says: Given a typical system, there are a wider variety of terminals than disk drives. Mainly because there are about 20 times more terminals on the system than disk drives. Also, given a typical system, terminal types tend to change more often than disk drive types. Mainly because there is an order of magnitude complexity difference between changing a terminal and changing a disk drive. Not to mention the fact that people who dial up a computer use whatever terminal they have at home. When was the last time you changed the type of drive you are using? When was the last time you added or swapped out a terminal? When was the last time someone connected a disk drive to your system over a phone? Your argument is fairly vacuous. It's quite true that the disk drive characteristics are hard coded in the kernel. But they don't change very often. You can afford to hard code disk drive characteristics. I'm not saying it's a good idea, but you can get away with it. You CAN'T afford to do that with terminals! And anyone that does so is painting himself into a corner. William, In your lead statement, you make a false assumtion about what a typical system is, and you also make a misleading statement about comparative numbers of terminals and disks. You say that there are 20x more ttys than disks. I don't know what your idea of a typical system is, but the typical system I have sitting next to me has one terminal and two types of disk on it. Your typical system might have twenty times as many terminals as disks, but I'd be surprised if it had twenty times as many different kinds of terminals as kinds of disks. Yes, I know that termcap supports a jillion kinds of terminals, but I dont know of a single installation that uses more than oh, twenty different kinds. Most use about five different kinds. Did you ever wonder why people use many kinds of terminals but not many kinds of disks? Perhaps it's because the software support is there (!). In the Bell System (where I had knowledge of the configuration of hundreds of systems), UNIX users have been stuck with certain hardware vendors even though the price and performance were certainly not competitive with current technology, all because of questionable software and hardware support worries. Judging by your answer, I can only assume that you haven't hacked up too many disk drivers to run with difference sizes or partitions. I haven't hacked up very many, I've hacked up too many. On my typical system, when I change my terminal, I don't really notice it because I just diddle my terminal name and termcap takes care of the rest. When I have to bring up a new flavor of disk, I have to noodle around in the damned driver. Right now, here at Masscomp, we have everything from floppies to 5.25" winnies to 8", 10", and 14" drives in various heights and girths. It's our business to stay abreast of current storage technologies, and we see a lot of different configurations fly by. Or, to contradict the way you put it, they change very often. We have many more kinds of disk drives around here than we have kinds of terminals, because disk technology is changing faster than terminal technolgy. You talk about what you can "afford to do" and what's a "good idea." You also called my argument of having easily configurable stacked disk i/o disciplines "fairly vacuous." My argument was either valid or not. I am either vacuous or not. Realize that "vacuous" is just a snot-nosed, recherche, euphemism for "stupid." After you called my idea vacuous, you presented the hard coding alternative this way: "I'm not saying it's a good idea, but you can get away with it." I'm not convinced. In this case, I'd say that my argument is valid, in MANY instances. There are lots of people out here who need to be able to integrate new hardware technology into their systems. Just because you don't, isn't sufficient reason to call us vacuous. Remember, kids, i/o devices all perform pretty much the same function. Classes of hardware may be grouped such that the hardware dependent parts are isolated, and the hardware independent parts are serviced by common software. This goes for disks and tapes, as well as we have learned that it goes for TTYs and CPUs. That's one to grow on. - Mr. T I pity the fool who calls me vacuous. - also Mr. T Andy Tannenbaum Masscomp Inc Westford MA (617) 692-6200 x274