cne6745@ritvax.isc.rit.edu (ELFERS, CN) (10/28/90)
This is my first post to this newsgroup so please, no flames! I want to use the Amiga UNIX as a part-time business (I'll provide ftp service for people who don't have access to a college, university, or company which has it.) Anyway, I will want to allow about 4-5 people dialed in but will want the option to allow up to 40 or so. Questions: 1) Is there some kind of serial port expansion out there which will allow multiple users? What is the limit for this peice of hardware? 2) Would I have to have a seperate modem for each user or is there some kind of special multiplexer I could use? 3) How many users will the AMIGA unix support thru dial-ins? What would I have to do to allow 40 dial-ins? Set up some kind of server? 4) There is a Multiuser Serial I/O for UNIX card put out by Chase Research which looks like it would do what I want but it is for the AT, MCA, and EISA bus. Is there any way to use all the hardware for the IBM with Amiga UNIX? I'm sorry if these appear naive. I would appreciate any info on above. Thanks. -Chris Elfers ============================================================================== AMIGA DOES IT BETTER! cne6745@ritvax.isc.rit.edu OR Chris Elfers cne6745@ritvax
zerkle@iris.ucdavis.edu (Dan Zerkle) (10/30/90)
In article <1990Oct28.161040.981@isc.rit.edu> cne6745@ritvax.isc.rit.edu writes: >This is my first post to this newsgroup so please, no flames! What? Have you EVER seen people get flamed here? Couldn't happen. >I want to use the Amiga UNIX as a part-time business (I'll provide ftp service >for people who don't have access to a college, university, or company which has >it.) First problem: Amiga UNIX isn't available to the general public in the US, yet. Will be soon, tho (I hope). >Anyway, I will want to allow about 4-5 people dialed in but will want the >option to allow up to 40 or so. Questions: > >1) Is there some kind of serial port expansion out there which will allow > multiple users? What is the limit for this peice of hardware? There are cards that give you two more serial lines. This will easily handle 4-5 users. However, you only have so many slots. Also, you will need a device driver for this hardware, which may or may not be there. See my comments below. >2) Would I have to have a seperate modem for each user or is there some kind of > special multiplexer I could use? You basically need a separate modem and telephone line for each user that is on at once. The more lines, the less likely your users get a busy signal. However, I believe you can buy boxes that have lots o' modems all at once. You still need to install and rent the phone lines. >3) How many users will the AMIGA unix support thru dial-ins? What would I have > to do to allow 40 dial-ins? Set up some kind of server? Amiga Unix is AT&T Sys5r4, so you can certainly configure it to handle as much as you want. >4) There is a Multiuser Serial I/O for UNIX card put out by Chase Research > which looks like it would do what I want but it is for the AT, MCA, and EISA > bus. Is there any way to use all the hardware for the IBM with Amiga UNIX? Not really. The BridgeBoard could use it, but that would not be nearly powerful enough to handle this kind of operation. Certain groups have proposed an add-on bus to let the amiga use ISA bus cards in native mode, but it's not commercially available, as far as I know, and I wouldn't trust it in Unix, anyway. >I'm sorry if these appear naive. I would appreciate any info on above. Thanks. If you knew the answers, you wouldn't have to ask, now would you? I considered this sort of thing, although not as an FTP site, so here are a few (hopefully useful) comments beyond what you've asked: You have a rather expensive proposition. You will probably take a while to break even on it, but I hope you can succeed. If you want to have 4-5 users on a Unix system, you should have plenty of memory. I don't know if Unix will change this, but the Amiga 500-2500 can handle at most 9 megabytes of memory, due to the way registers & such are mapped. I would recommend at least 16 megs for this. The Amiga 3000 can handle up to 18 megs on the motherboard, and practically infinite amounts through expansion boards, so you should probably use a 3000 for this project. Also, the 3000 has a 32-bit data path on its bus. This is very important when running Unix multi-user. Unfortunately, there are no 32-bit RAM cards now available for the 3000, so you have to use the 16-bit cards, which substantially degrade performance. If you really want 40 users logged on at a time, I really can't recommend an Amiga. Right now, the best CPU you can get for the Amiga is a 68030, and I don't think it could handle the kind of throughput you want without getting bogged down. Sometime it will be possible to run a 68040 on the Amiga. This will provide substantially improved throughput and might handle it, but I doubt it. Another issue is the disk. Even with 16 megs of RAM, you will have a lot of swapping and paging going on with 5 users on at a time. You will need a lot of disk space, and you will need a lot of speed. Of course, if your users are getting stuff via FTP, you need TONS of space, although this disk space doesn't need to be quite as fast. Again, I would recommend the 3000 for this, as it has a 32-bit bus and SCSI controller (I think), and could handle it better. You will need an external "shoebox" disk to handle this sort of thing. Again, due to the limitations on the disk, I can't recommend an Amiga for 40 users. Although the SCSI standard is plenty fast for small systems, it just won't cut it on that scale. Also, SCSI is a daisy-chained set up. You can only get to one device at a time. You'd want parallel access for that kind of load. I don't know if the 3000 could handle a second SCSI controller, but if if could, it would help a lot. You get 7 disks per controller. You probably wouln't want your computer handling all of the serial i/o. Besides, all those serial cards add up. A better solution is to get a terminal server. It can handle lots of serial lines, and takes the load off of the main computer. A division of Hughes Aircraft makes servers that handle either 8 or 64 serial lines. They are hooked into an ethernet, and you can get from the server to the other systems on the net. If you are planning on providing FTP service, you probably already have an ethernet hook up on your computer, so this would work out well. Also, some of your users are going to want 9600 bps and faster modems, but you don't have to provide only these expensive modems. You can get away with mixing in some cheaper ones. FTP service is extremely expensive to set up. You first have to get registered and approved by some sort of bureacracy, which I know very little about. Then, you need to buy an expensive gizmo called an IMP (InterNet Message Processor). Then, you need to buy at least two very high-speed modems (no, 9600 bps isn't good enough). Then, you need to install and rent two dedicated telephone lines to two other internet sites, so other sites can route through your site. Of course, if you already have this sort of thing set up, you're in good shape. I'm not saying that this sort of thing isn't possible for 40 users. What you would have to do is set up a network of Amigas. They could have one file server to take care of the disks, and maybe 6-8 3000's that people could log in on. If you had the terminal server, people could choose which system they want to log in on. It would be truly beautiful. It would also cost a hell of a lot. Unfortunately, it is not yet possible in the US, as Amiga Unix is not readily available. If you are in a hurry, I would recommend you either get a big minicomputer, or a network of workstations. There are lots of sales weenies at IBM, Hewlett-Packard, Sun, and NeXT who would just love to sell you some computers. If you don't have that kind of budget to set up FTP, you can still get into the game using UUCP. You will need some local site to give you a "feed", and you'll need a fast modem to get to it, but you can do it for much less than FTP. You can still get files from archives, but it is much slower (days, instead of minutes). Of course, if you spend a couple grand on disk space, you can set up an archive at your own site, and let people download directly from there. People would just love that! You wouldn't even need Unix, but could just set up a multi-user BBS. Whoops. It's time for lunch. Good luck! Dan Zerkle zerkle@iris.ucdavis.edu (916) 754-0240 Amiga... Because life is too short for boring computers.
fnf@riscokid.UUCP (Fred Fish) (10/30/90)
In article <7885@ucdavis.ucdavis.edu> zerkle@iris.ucdavis.edu (Dan Zerkle) writes: >In article <1990Oct28.161040.981@isc.rit.edu> cne6745@ritvax.isc.rit.edu writes: >>3) How many users will the AMIGA unix support thru dial-ins? What would I have >> to do to allow 40 dial-ins? Set up some kind of server? > >Amiga Unix is AT&T Sys5r4, so you can certainly configure it to handle >as much as you want. People who have played with SVR4 at shows have previously reported on usenet that it is limited to 2 users for licensing reasons. Hope they change that in the released version, or at least provide an unlimited user version for only a small surcharge. -Fred