When I tried to login through a linux machine through ssh, I was asked for selection of two Terminal types: VT100 (Wyse 85) and vt100 (BS erase).

I searched in google, but I couldn't get the answer.

Can any one please explain, what is difference between them and which one to select ?

  • That sounds like a quite old SSH client (or perhaps an old server configuration...) What are you using to connect? – grawity Aug 28 '14 at 8:00
  • I am connecting from Xwin to RHEL5 server through SSH. But, I want to know the difference between two.. so that I can select the right one. – Rajasekhar Aug 29 '14 at 10:08

For your purposes, "VT100" is the same as "vt100".

"wy85" refers to the Wyse-85.

ncurses has terminal descriptions for wy85 and vt100 (or vt102).

You're talking about a terminal emulator, which of course may differ from the actual terminal. But supposing that the terminal emulator provided by Xwin were complete, the place to look for an answer is in the report by the infocmp program. Here is the output of a report:

$ infocmp -p vt100 wy85
comparing vt100 to wy85.                                                       
    comparing booleans.
        hs: F:T.
        mir: F:T.
    comparing numbers.
        vt: 3, NULL.
        wsl: NULL, 80.
    comparing strings.
        cbt: NULL, '\E[Z'.
        civis: NULL, '\E[?25l'.
        cnorm: NULL, '\E[?25h'.
        dch: NULL, '\E[%p1%dP$<3*>'.
        dch1: NULL, '\E[P$<3>'.
        dim: NULL, '\E[2m'.
        dl: NULL, '\E[%p1%dM$<3*>'.
        dl1: NULL, '\E[M$<3>'.
        dsl: NULL, '\E[40l'.
        ech: NULL, '\E[%p1%dX'.
        enacs: '\E(B\E)0', '\E)0'.
        flash: NULL, '\E[30h\E\,$<300/>\E[30l'.
        fsl: NULL, '\E[1;24r\E8'.
        ich: NULL, '\E[%p1%d@$<4*>'.
        il: NULL, '\E[%p1%dL$<5*>'.
        il1: NULL, '\E[L$<5>'.
        invis: NULL, '\E[8m'.
        ip: NULL, '$<3>'.
        is1: NULL, '\E[62;1"p\E[?5W'.
        is2: NULL, '\E[2;4;20;30l\E[?1;4;10;16l\E[12h\E[?7;8;25h$<16>'.
        is3: NULL, '\E>\E(B\E)0\017\E[m'.
        ka1: '\EOq', '\EOw'.
        ka3: '\EOs', '\EOy'.
        kb2: '\EOr', '\EOu'.
        kc1: '\EOp', '\EOq'.
        kc3: '\EOn', '\EOs'.
        kcub1: '\EOD', '\E[D'.
        kcud1: '\EOB', '\E[B'.
        kcuf1: '\EOC', '\E[C'.
        kcuu1: '\EOA', '\E[A'.
        kdch1: NULL, '\E[3~'.
        kf0: '\EOy', NULL.
        kf10: '\EOx', '\E[21~'.
        kf11: NULL, '\E[23~'.
        kf12: NULL, '\E[24~'.
        kf13: NULL, '\E[25~'.
        kf14: NULL, '\E[26~'.
        kf15: NULL, '\E[28~'.
        kf16: NULL, '\E[29~'.
        kf17: NULL, '\E[31~'.
        kf18: NULL, '\E[32~'.
        kf19: NULL, '\E[33~'.
        kf20: NULL, '\E[34~'.
        kf5: '\EOt', NULL.
        kf6: '\EOu', '\E[17~'.
        kf7: '\EOv', '\E[18~'.
        kf8: '\EOl', '\E[19~'.
        kf9: '\EOw', '\E[20~'.
        kfnd: NULL, '\E[1~'.
        khlp: NULL, '\E[28~'.
        khome: NULL, '\E[26~'.
        kich1: NULL, '\E[2~'.
        knp: NULL, '\E[6~'.
        kpp: NULL, '\E[5~'.
        kslt: NULL, '\E[4~'.
        lf1: 'pf1', 'PF1'.
        lf2: 'pf2', 'PF2'.
        lf3: 'pf3', 'PF3'.
        lf4: 'pf4', 'PF4'.
        rmir: NULL, '\E[4l'.
        rmkx: '\E[?1l\E>', '\E>'.
        rs1: NULL, '\E[13l\E[3l\E!p'.
        sgr: '\E[0%?%p1%p6%|%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;m%?%p9%t\016%e\017%;$<2>', '\E[0%?%p2%t;4%;%?%p3%p1%|%t;7%;%?%p4%t;5%;%?%p5%t;2%;%?%p6%t;1%;%?%p7%t;8%;m%?%p9%t\016%e\017%;'.
        smir: NULL, '\E[4h'.
        smkx: '\E[?1h\E=', '\E[?1l\E='.
        tsl: NULL, '\E[40h\E7\E[25;%i%p1%dH'.

Those NULL items indicate that the feature is missing. According to this, wy85 has definitions for function-keys (which your PC keyboard probably has) and that the terminal supports a separate status line (far less likely).

If your chosen terminal description lacks a feature (such as function keys), most programs will not know how to handle those features.

A few differences are just due to the way the vt100 terminal description evolved (essentially from a BSD termcap entry), so that flash is missing although the vt100 certainly supported that. The BSD termcap library did not.

The notes for the wy85 terminal description indicate that the (original) terminal was emulating a VT220 (e.g., the ech line), but that is inconsistent with the cnorm and civis (show/hide the cursor), which (see XTerm Control Sequences mentioning DECTCEM) came from the next model up, e.g., VT320.

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