mac1@ra.MsState.Edu (Cheema) (03/19/91)
I wonder if its only me or everybody else is in the same boat. I have a 1200 baud modem and when I am downloading some long files say around 400k it makes me wait for hours (normally 4 to 6 hrs). I have ordered another 2400 baud modem but still I think I still will have to wait at least a couple of hours for a file to get downloaded. Is this weird or normal ? I am currently using Xmodem protocol. Does terminal program has any effect on this. Also what to do with files that are longer than 880K. i.e they can't be put onto one diskheema
spworley@athena.mit.edu (Spaceman Spiff) (03/19/91)
You DO seem to have problems. XModem is pretty efficient, and for a 400K file, it should take less than an hour to download (400K *1024 bytes/K * 8 bits/byte * 1 second/1200 bits * 1 hour/3600 secs = .75 hours + a little extra for overhead. Terminal programs shouldn't make a speed difference, though protocols (X Y Z modem, for example) do. Perhaps your phone lines are SO noisy there are a LOT of errors and retransmissions. If you use JRComm or NCOMM (my favorate) you get a display of the number of errors per file, and a characters per second display. My 2400 baud modem (with Zmodem protocol) usually goes at about 230 chars/second. You should be getting at least 100. I'm hoping you know about file compression. Compressing with LHARC or ZOO will reduce file size (and transfer time) by a third or more. I hope your new modem solves your problem. -Steve ------------------------------------------------------------------------------ Steve Worley spworley@athena.mit.edu ------------------------------------------------------------------------------
dtiberio@csserv2.ic.sunysb.edu (David Tiberio) (03/20/91)
In article <mac1.669336994@Ra.MsState.Edu> mac1@ra.MsState.Edu (Cheema) writes: > > I wonder if its only me or everybody else is in the same boat. I have a 1200 >baud modem and when I am downloading some long files say around 400k it makes >me wait for hours (normally 4 to 6 hrs). I have ordered another 2400 baud I am not surprised. Usually, xmodem at 1200 gives 90 cps, while zmodem can get 110 cps at 1200 baud. Always try to use zmodem, since it can download one file in two parts (if the system crashes during a download, you can start where you left off). At 2400 baud, expect twice the above cps, with a max zmodem of about 240 cps. At most I have gotten 280 cps xmodem and 1760 cps with ymodem (at 19200 baud). Always avoid Kermit (really slow). >modem but still I think I still will have to wait at least a couple of hours >for a file to get downloaded. Is this weird or normal ? > I am currently using Xmodem protocol. Does terminal program has any effect on >this. Also what to do with files that are longer than 880K. i.e they can't be >put onto one diskheema Always try to use zmodem, or then try ymodem. They are 30% faster and more reliable. If a file is over 800k, then it can be split if it is a disk compressor. If it is a normal archive, then only decompress enough to fit in each disk (or all of it in ram). David Tiberio SUNYStonyBrook2-3481 DDD MEN isOP
king@motcid.UUCP (Steven King) (03/21/91)
In article <mac1.669336994@Ra.MsState.Edu> mac1@ra.MsState.Edu (Cheema) writes: > > I wonder if its only me or everybody else is in the same boat. I have a 1200 >baud modem and when I am downloading some long files say around 400k it makes >me wait for hours (normally 4 to 6 hrs). I have ordered another 2400 baud >modem but still I think I still will have to wait at least a couple of hours >for a file to get downloaded. Is this weird or normal ? > I am currently using Xmodem protocol. Does terminal program has any effect on >this. Also what to do with files that are longer than 880K. i.e they can't be >put onto one diskheema Let's do some ciphering... A good rule of thumb is to figure 10 bits per character, so at 1200 baud you can transfer a max of 120 characters per second. 400K = 409,600 characters, so you can figure the minimum time to transfer is 3413 seconds or .95 hours. Xmodem is a dog (send 128 characters, wait for an ACK, send 128 characters, wait for an ACK...) so I'd double that. I'd expect the transfer to take about 2 hours. Your terminal program *shouldn't* make a difference, but in practice it might. If you've got a poor program it may be wasteing time before it sends the ACK back to the machine you're downloading from. This will add to your overall transfer time. Also, if you've got noisy lines (do you see bursts of garbage when you're logged on?) packets will need to be retransmitted. That will also add to the transfer time. 4 to 6 hours is much longer than expected, but not outside the realm of possibility. If you can, change to Zmodem. Zmodem is a *much* faster protocol because it doesn't send ACKnowledgements back to the host after every so many characters. Instead, it will only send replies to the host during setup and when it detects an error. Also, the CRC error-detection routine Zmodem uses is more sensitive to errors than the checksum routine commonly used by Xmodem. If you've got files longer than 880K and you've only got floppies... Well, you're kind of screwed. If you can, unpack the large file on the host system and download the smaller individual file. If you can't manage that for whatever reason, you're screwed. The only solutions are to buy a hard drive (or one of the new AE high-density floppy drives) or find a friend with one who will transfer it for you. -- ---------------------------------------------------+--------------------------- The amount of work that actually got done during | Steven King the week is inversely proportional to the number | Motorola Cellular of entries in 'timetool'. | ...uunet!motcid!king
hrmeyer@ucselx.sdsu.edu (meyer h) (03/21/91)
In article <mac1.669336994@Ra.MsState.Edu> mac1@ra.MsState.Edu (Cheema) writes: > > I wonder if its only me or everybody else is in the same boat. I have a 1200 >baud modem and when I am downloading some long files say around 400k it makes >me wait for hours (normally 4 to 6 hrs). I have ordered another 2400 baud The slow transfer rate you are getting is exactly what I would expect for XModem *AT 300 BAUD*. Is your terminal program set to 1200 baud? When you establish connection, do you get a "CONNECT 1200" message instead of "CONNECT"? Are you connecting to a host other than some BBS which may only be capable of 300 baud? Harry R. Meyer hrmeyer@ucselx.sdsu.edu
Harvey_Taylor@mindlink.UUCP (Harvey Taylor) (03/21/91)
In <mac1.669336994@Ra.MsState.Edu>, mac1@ra.MsState.Edu (Cheema) writes: | [...] | I have a 1200 baud modem and when I am downloading some long files |say around 400k it makes me wait for hours (normally 4 to 6 hrs). | [...] | I am currently using Xmodem protocol. Are these local calls or are you going through a packet network somewhere? A packet net like PCPursuit makes Xmodem painful. | Does terminal program has any effect on this. Minimal. -het "Ah, but you do not understand. To be on the wire is life. And the rest is waiting." Papa Wallenda Harvey Taylor Meta Media Productions uunet!van-bc!rsoft!mindlink!Harvey_Taylor a186@mindlink.UUCP
WGLP09@SLACVM.SLAC.STANFORD.EDU (03/26/91)
Harvey -
While I think of it, seeing your post: You sent me mail once
about MBRTest. I tried replying several times but it was tossed back in
my face every time. The short answer was: with the 1-Meg Agnus you must
use "setpatch r" in your startup.
Willy.
PS: Sorry for this being in the wrong topic...