KARNEY%PPC.MFENET@NMFECC.ARPA (08/05/87)
I have observed strange behavior with type-ahead when doing single character terminal input via SET HOST. Two examples: (A) I have a file FOO.TXT which contains 100 lines of which the first two are: line 00 line 00 line 00 line 00 line 00 line 00 line 01 line 01 line 01 line 01 line 01 line 01 I SET HOST to a VAX, run Carosso's pseudo TTY test program PTY.PAS (the release of about a month ago), and execute $ type foo.txt FOO.TXT appears unscathed on my terminal. If however I type ahead while the file is being typed, the lines get reordered!!! Here is the order they came in when I typed a single letter 'a' on about line 10. 00 01 02 03 04 05 06 07 08 13 09 14 10 15 11 16 12 17 26 18 27 19 28 20 29 21 30 22 31 23 32 24 33 25 34 39 35 40 36 41 37 42 38 43 52 44 53 45 54 46 55 47 56 48 57 49 58 50 59 51 60 65 61 66 62 67 63 68 64 69 78 70 79 71 80 72 81 73 82 74 83 75 84 76 85 77 86 91 87 92 88 93 89 94 90 95 96 97 98 99 Note, all the lines appeared, but in a jumbled order. This was observed at both 9600 baud and 2400 baud. FOO.TXT is stream_lf. The original SET HOST is necessary to get this behavior. If you connect directly to the machine running PTY everything works OK. I believe it is dependent on PTY doing single character input. Asbed Bedrossian's PHOTO program which does multi-character input functions correctly. (B) I have noticed a similar behavior in GnuEmacs via SET HOST. If you type ahead to it, while it is redrawing the whole screen, it displays lines alternately in the top and bottom halves of the screen. The final display is correct, presumably because each line begins with a cursor positioning command. I used to think this was some quirk of Emacs. Now it looks like it's some DEC problem. The crucial ingredients appear to be: (1) SET HOST (2) Single character QIO reads on the terminal (3) Typing ahead Has anyone else noticed this? Is there an explanation? Is there a fix? Charles Karney Plasma Physics Laboratory Phone: 609/683-2607 Princeton University MFENet: Karney@PPC.MFENET PO Box 451 ARPANet: Karney%PPC.MFENET@NMFECC.ARPA Princeton, NJ 08544-0451 Bitnet: Karney%PPC.MFENET@ANLVMS.BITNET CC: INFO-VAX@SRI-KL.ARPA KVC%ENGVAX@OBERON.USC.EDU ASBED@OBERON.USC.EDUubje64 eno69