jch+@cs.cmu.edu (Jonathan Hardwick) (06/19/91)
Question for the net: A housemate has an original Big Blue IBM PC, running at the blazing speed of 4.77MHz. We want to use this as a dumb terminal to access our university workstations. The university offers 2400 bps service with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV modems. We'd really like the extra speed if possible. Is the PC going to be able to keep up with 19200 bps? How about 9600 bps? It must be at least 5 years since I touched a PC, so I've lost any idea I may once have had for the speed of these beasts... Oh, and if the PC *can't* keep up, what sort of motherboard upgrade would we need? 10 MHz 8086? 80286? Thanks for any information, Jonathan Hardwick, School Of Computer Science, Carnegie Mellon Univ.
tau-ceti (06/19/91)
jch+@cs.cmu.edu (Jonathan Hardwick) writes: > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? I think not. And, if my aged, infirm memory is correct, it isn't the motherboard's fault. It's the inherent capability of the chip onboard your comm port. You need a 16 bit card to accomplish this speed. How about 9600 bps? Yes, I believe, given the right card, you can do 9600 ok, though. > > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? Given the fact that a 286 12 mz motherboard for a PC runs less than 150 dollars these days, depending upon how robust you will need it to be, I think you should upgrade, anyway. Just make certain it will fit the OEM IMB case. Some will, some won't. > > Thanks for any information, > Jonathan Hardwick, School Of Computer Science, Carnegie Mellon Univ. --------------------------------------------------------------------------- dave@kharma (Dave Laird) | (___) | The Computer Concern, Springdale SYSOP: Used Kharma Lot BBS | (O O) | Washington 509-233-8474 *HST* _____________________________| (._.) |___________________________________ ++ isc-br!tau-ceti!dogear!kharma!dave ++
tnixon@hayes.uucp (06/19/91)
In article <1991Jun18.201125.6198@cs.cmu.edu>, jch+@cs.cmu.edu (Jonathan Hardwick) writes: > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? Before coming to Hayes, I worked for Datamaxx USA Corp, writing firmware for terminal emulators. Their biggest-selling product was based on a Motorola 6800 processor running at 1 MHz, and supported up to 9600bps -- without flow control, and without ever losing data! So, I _know_ that a 4.77MHz processor _can_ support 9600, even 19200, _if_ your comm software is well written. That's the real trick: finding a program that is efficiently written, properly supports flow control, scrolls fast, properly schedules writes to disk to avoid slowdowns, etc. Hayes Smartcom Exec is one such program (its what I use), but I'm sure you can get plenty of recommendations for good programs that can keep up with 9600 or 19200 on a 4.77 MHz PC. If you're doing anything fancy on the PC (running TSRs that hook into the timer interrupt, or a LAN card, or RAMdisk), then you may want to invest in a buffered serial port card like Hayes ESP. This provides 1024 bytes of buffer in the hardware, plus automatic hardware flow control, so even if the main CPU gets a bit behind tending to other things, you still don't lose characters. It's a lot cheaper and easier than getting a new motherboard, assuming you're using a modem that has flow control. So, anyway, my advice is, "go for it". -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net
ted@isgtec.uucp (Ted Richards) (06/19/91)
In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > Question for the net: > > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? I have some bad news for you. I have one of these geriatric beasts, too, and it doesn't even come close to keeping up at 9600 baud. The problem is in the screen updates, not the comms port, which manages file transfers at almost full speed (~ 860-920 cps). The speed varies depending on the comms programm. I have tried Procomm, Telix and two varieties of MS_kermit. Telix is really awful (unfortunate, because I like the programm a lot). Even with Telix doing its own screen updates (the fastest mode), it fills the screen at perhaps 300 cps when scrolling, somewhat better when clearing the screen first. The latest Kermit is not much better. Procomm was, I think, a little faster, but I tried it a year ago, so I don't remember exactly. The best performance, perhaps 500-600 cps, comes from a very old copy of Kermit, dated 1982 or 1983 that I found lying around on an old diskette. Perhaps someone else has found another comms program that can keep up? By the way, I am using a Telbit T1000 on my end, talking to a T2500 (at 9600 baud) at work. > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? Can't help you here, since I haven't done anything about it (I'm saving up for a 386-25, myself). -- Ted Richards ...uunet!utai!lsuc!isgtec!ted ted@isgtec.UUCP ISG Technologies Inc. 3030 Orlando Dr. Mississauga Ont. Canada L4V 1S8
mcdonald@aries.scs.uiuc.edu (Doug McDonald) (06/20/91)
In article <1155@isgtec.UUCP> ted@isgtec.uucp (Ted Richards) writes: >In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: >> Question for the net: >> >> A housemate has an original Big Blue IBM PC, running at the blazing >> speed of 4.77MHz. We want to use this as a dumb terminal to access >> our university workstations. The university offers 2400 bps service >> with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV >> modems. We'd really like the extra speed if possible. Is the PC >> going to be able to keep up with 19200 bps? How about 9600 bps? > >I have some bad news for you. I have one of these geriatric beasts, >too, and it doesn't even come close to keeping up at 9600 baud. The >problem is in the screen updates, not the comms port, which manages file >transfers at almost full speed (~ 860-920 cps). > >The speed varies depending on the comms programm. I have tried Procomm, >Telix and two varieties of MS_kermit. Telix is really awful >(unfortunate, because I like the programm a lot). Even with Telix doing >its own screen updates (the fastest mode), it fills the screen at >perhaps 300 cps when scrolling, somewhat better when clearing the screen >first. The latest Kermit is not much better. Procomm was, I think, a >little faster, but I tried it a year ago, so I don't remember exactly. > >The best performance, perhaps 500-600 cps, comes from a very old copy of >Kermit, dated 1982 or 1983 that I found lying around on an old diskette. > >Perhaps someone else has found another comms program that can keep up? > >By the way, I am using a Telbit T1000 on my end, talking to a T2500 (at >9600 baud) at work. > >> Oh, and if the PC *can't* keep up, what sort of motherboard upgrade >> would we need? 10 MHz 8086? 80286? > >Can't help you here, since I haven't done anything about it (I'm saving >up for a 386-25, myself). > >-- A plain PC at 4.77 MHz can EASILY keep up with 19200 baud including output to the screen. You just have to have an EGA card or higher (or maybe a CGA or mono, I've never tried). You do it by scrolling NOT by actually moving characters around in video memory, but by setting up a double-length video buffer (twice the length of the screen) and keeping TWO copies of your text in it in double-circular-buffer mode. You then just move the start-of-memory pointer on the video card to scroll. And, amazingly enough, on my 386 this works fine up to 9600 baud **in graphics mode**!!!! Doug McDonald
pshuang@athena.mit.edu (Ping-Shun Huang) (06/20/91)
In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > We'd really like the extra speed if possible. Is the PC going to be > able to keep up with 19200 bps? How about 9600 bps? I think the original IBM-PC would be hard pressed to keep up with even 9,600 baud modems, much less a 19,200 connection. It may be just barely possible for this to work if you have (a) a communication program which doesn't impose too much overhead -- obviously comm programs which run under Windows are out, but character-based comm programs vary widely in the CPU time they "waste" in doing other processing; I would try {commo}, which is a very un-memory-intensive, un-CPU-intensive shareware comm program; (b) a serial port which knows how to buffer incoming characters (FIFO = First In, First Out). There's a serial port chip called 16xxxA, which can buffer a few characters. I don't know the details about the new Hayes smart serial ports, but they almost certainly also implement buffering, too. If you want to upgrade to better CPU, I would imagine a 12Mhz 80286 should do the job... probably better if you still consider (a) & (b). -- Above text where applicable is (c) Copyleft 1991, all rights deserved by: UNIX:/etc/ping instantiated (Ping Huang) [INTERNET: pshuang@athena.mit.edu]
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (06/20/91)
>> A housemate has an original Big Blue IBM PC, running at the blazing >> speed of 4.77MHz. We want to use this as a dumb terminal to access >> our university workstations. The university offers 2400 bps service >> with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV >> modems. We'd really like the extra speed if possible. Is the PC >> going to be able to keep up with 19200 bps? How about 9600 bps? >I have some bad news for you. I have one of these geriatric beasts, >too, and it doesn't even come close to keeping up at 9600 baud. The >problem is in the screen updates, not the comms port, which manages file >transfers at almost full speed (~ 860-920 cps). Hmmmm... I am at this moment using a Leading Edge model D with a direct serial line running at 9600 baud, with a Sytek box at the other end and I don't have any trouble when the switch on the back is set at 4.77 MHz. If your screen scrolls too slowly, try running something like FansiConsole to speed it up (I do). -- ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS ! -------------------------------------------------------------------------------
curt@cynic.wimsey.bc.ca (Curt Sampson) (06/20/91)
In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? > > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? I've got a similar question, actually. I'm runing SCO Xenix 2.3.2 on a 12 MHz 80286. When testing with a V.32 modem and the FAS driver (using a 16550 with the buffer turned on) I'm only getting about 450 cps. Things seem to be configured correctly, so I'm at a loss to see what could be causing this. Could it be that my CPU just doesn't have enough oomph to work faster? I'd appreciate any comments or experiences that anyone can share. cjs -- | "I suspect the principle difference between us is | that I spend a lot of time walking around the tree | trying to find the best way to shake it while you Curt Sampson | are more concerned with whether an axe or a chain-
caf@omen.COM (Chuck Forsberg WA7KGX) (06/20/91)
A 4.77 MHz PC can keep up with a 9600 bps modem. A 16550A/AFN UART chip helps; you'll need it to make up for newer versions of DOS. A CGA slows things down. Use an MDA, EGA or VGA for more speed. Unfortunately, upgrading the display may cost more than the PC is worth. Most programs scroll by copying memory. The alternate approach (of necessity on 6800 systems) does not work well when scrolling regions are set. I would suggest downloading a copy of ZCOMM from TeleGodzilla or a local BBS. It is about as quick as they come unless tested by PC Magazine "experts". If the computer has a CGA try setting ZCOMM's "display warpdrive" to speed things up. Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ Omen Technology Inc "The High Reliability Software" 17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406 TeleGodzilla:621-3746 FAX:621-3735 CIS:70007,2304 Genie:CAF -- Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ Omen Technology Inc "The High Reliability Software" 17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406
U39648@uicvm.uic.edu (From The Mind Of) (06/20/91)
>A housemate has an original Big Blue IBM PC, running at the blazing >speed of 4.77MHz. We want to use this as a dumb terminal to access >our university workstations. The university offers 2400 bps service >with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV >modems. We'd really like the extra speed if possible. Is the PC >going to be able to keep up with 19200 bps? How about 9600 bps? It >must be at least 5 years since I touched a PC, so I've lost any idea I >may once have had for the speed of these beasts... > >Oh, and if the PC *can't* keep up, what sort of motherboard upgrade >would we need? 10 MHz 8086? 80286? Your PC should be able to keep up if you replace the UART that controls your serial port. It's probably an 8250, so you can replace it with a NS16550A directly, which has a FIFO buffer to help handle high speed transfers, especially on slower machines or fast machines running multiple tasks. This chip is inexpensive, and you should be able to get one for under $20. - Darius ========================================================================= BITNET: U39648@UICVM | "I'd rather laugh with the sinners Internet: u39648@uicvm.uic.edu | than cry with the saints, ====================================| the sinners are much more fun, "Don't set fire to strangers." | and only the good die young." - Mr. Zarniwoop | - Billy Joel
wb8foz@mthvax.cs.miami.edu (David Lesher) (06/21/91)
It's important to define what you mean by "keep up" in this case.
Case in point: Several years back, I was flogging a wideband WAN system
to get some idea how well it might handle some big graphics dumps.
I used both 11/34's and that new-fangled 11-750 {I said it was a few
years ago, remember?} to spit out characters as fast as possible. For
destinations, I used a variety of terminals {i.e. whatever I could
snitch from folk's offices when they went to meetings;-} such as those
somewhat weird-looking HP things, VT-100's, AJ's, etc.
Not a one could keep up @ 19,200. They just could not write fast
enough. They would X-off back, catch a breath, and start again just
fine, but without flow control, forget it. Now since nobody could read
that fast, that's no problem. But I did have limited access to two 19"
Tek graphics boxes with price tags to match. They did keep up. Maybe
the 80286 aux-processors helped ;-}
On a PeaSea, I suspect the video would be the biggest drain. Stick to
a mono text card, if you can FIND one, and I bet it will work, with
flow control, of course.
BTW, if I fed all 8 ports on the Sytek/Localnet box @ 19,200, its z-80
got very confused, and crashed every time. Wonder why;-?
--
A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu
& no one will talk to a host that's close............(305) 255-RTFM
Unless the host (that isn't close)......................pob 570-335
is busy, hung or dead....................................33257-0335robertsw@gtephx.UUCP (Wild Rider) (06/25/91)
In article <1991Jun20.125829.15405@omen.COM> caf@omen.COM (Chuck Forsberg WA7KGX) writes: >A 4.77 MHz PC can keep up with a 9600 bps modem. as part of a project i was involved in, i wrote a vt100 comm program with the requirement that it had to keep up with a dec vt100 terminal at 9600 bps, even when running on a 4.77mhz pc. it did, but just barely. the comm program (called pc100) was (is) written entirely in c, yes, even the comm port isr. ("assembly? we don't need no steenkin' assembly!" :-) the default receive buffer was 2k, which created an "interesting" delay when you pressed ctrl-s to suspend. :-) actually, with proper handshaking & buffering, even a plain old pc should be able to just keep it's head above water at 19.2kbps. don't expect any background/foreground stuff, though! :-) >-- >Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf >Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ > Omen Technology Inc "The High Reliability Software" >17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406 i suppose in the presence of a wizard like chuck forsberg, any pc would perform well, even at 9600 bps. :-) cheers, wr (the wild rider) -- Wallace Roberts, AG (formerly GTE) Communication Systems, Phoenix, AZ UUCP: ...!{ncar!noao!asuvax | uunet!zardoz!hrc | att}!gtephx!robertsw Internet: gtephx!robertsw@asuvax.eas.asu.edu Bike: '82 GS1100L Suz voice: (602)581-4555 fax: (602)582-7624 Cage: '89 Mustang GT
skipm@dorsai.com (Dorsai SysOp) (06/25/91)
dogear!kharma!dave@isc-br!tau-ceti writes: > Given the fact that a 286 12 mz motherboard for a PC runs less than 150 > dollars these days, depending upon how robust you will need it to be, I think > you should upgrade, anyway. Just make certain it will fit the OEM IMB case. > Some will, some won't. > Some manufacturers make some really small mini-AT's that are square in size, and fit in the space of about 1/3 a full-sized AT board. I've mounted these in original IBM PC cases, and with a little work figuring out where you should put standoffs, they're fine. Be care with what model you select - make sure the RAM, if it's the SIMM or SIP type is not near the drive cages - you'll have a hard time fitting the board in if you can at all. Be sure too to place electrical tape or some sort of insulating material on the border edges of the case where the original PC motherboard sat, otherwise you'll short the whole shebang out. Skip ************************************************************************** ** SkipM@DORSAI.com - The Dorsai Embassy / Dorsai Diplomatic Mission ** ** (Systems Manager) - Consulate : (212) 431-1944 ** ************************************************************************** ** "The difference between a good man, and a bad man, is the choice of ** ** cause." - Unknown ** **************************************************************************