Remote Desktop

Remote Desktop

This page presents methods to use the XO to access remote computers, either through a shell (a command line for linux users) or graphically.

A comparison of remote desktop sofwares.

Graphical access

NoMachine NX

The NoMachine company sells their NX solution and also offer a free version for personal use. NX is a special compression method for the X protocol which allows to access remote graphical display, even on low bandwith connections like phone lines.

Compared with VNC, NX uses a encrypted communication between the server and the client, is able to forward sound and printers, resume deconnected sessions or share a view, and is more responsive (try it to see).

There is also a free and open-source version of the software FreeNX for the server part.

Initially, the client connects to a remote X server. The commercial NX client is also able to connect to VNC and RDP (Windows Terminal Server).

Setup on the server

Download the packages corresponding to your server. You need to download 3 packages (client, node, server). You need to install them in that order. I won't document that operation as it depends on you server configuration.

# Install client
# Install node
# Install server

Setup on the XO

Download the NoMachine NX client for linux. Start the terminal activity. Switch to root user.

$ su -l

The NX client depends on the audio file library that you must install first.

# yum install audiofile

Next install the client.

# rpm -ivh nxclient-3.0.2-2.i386.rpm

Connecting to the server from the XO

You need to have a user account on the server to be able to open a session on it! NoMachine NX server let you manage user accounts distincts from the Unix users, but by default it uses Unix accounts.

On the XO, open the Terminal activity. Start the nxclient.

$ nxclient

Enter the host name of the server, your user name and password. In the advanced configuration, you can set other options like the type of session you want to use (KDE, Gnome...), the speed of the connection (LAN, DSL...). I suggest to change the cache configuration to use 16 MB RAM and no cache on disk.

Validate the form to connect to the server.

Keyboard mapping

The special keyboard layout of the XO is not correctly mapped by the nxclient (which sees it as pc102 instead of pc105), at least when the XO connects to a Debian Etch server. For instance, on a KDE session, the arrow keys are not working, and the Up key thinks it is a PrntScr key and starts ksnapshot! Not really handdy... Here is a manual workaround.

When connected remotely to the server, open a terminal and register this keymap configuration with X.

$ xmodmap xomodmap.keys

Content of the xomodmap.keys file

 keycode   8 =
 keycode   9 = Escape
 keycode  10 = 1 exclam exclamdown exclamdown exclamdown exclamdown
 keycode  11 = 2 at notsign notsign notsign notsign
 keycode  12 = 3 numbersign U0300 U0300 U0300 U0300
 keycode  13 = 4 dollar U0301 U0301 U0301 U0301
 keycode  14 = 5 percent U0306 U0306 U0306 U0306
 keycode  15 = 6 asciicircum U030A U030A U030A U030A
 keycode  16 = 7 ampersand U0302 U0302 U0302 U0302
 keycode  17 = 8 asterisk U0324 U0324 U0324 U0324
 keycode  18 = 9 parenleft U0307 U0307 U0307 U0307
 keycode  19 = 0 parenright U0308 U0308 U0308 U0308
 keycode  20 = minus underscore U0304 U0304 U0304 U0304
 keycode  21 = equal plus U0303 U0303 U0303 U0303
 keycode  22 = BackSpace Terminate_Server
 keycode  23 = Tab ISO_Left_Tab
 keycode  24 = q Q Greek_omega Greek_OMEGA Greek_omega Greek_OMEGA
 keycode  25 = w W oslash Oslash oslash Oslash
 keycode  26 = e E oe OE oe OE
 keycode  27 = r R U0327 U0327 U0327 U0327
 keycode  28 = t T U032E U032E U032E U032E
 keycode  29 = y Y U0325 U0325 U0325 U0325
 keycode  30 = u U U032D U032D U032D U032D
 keycode  31 = i I U032C U032C U032C U032C
 keycode  32 = o O U0323 U0323 U0323 U0323
 keycode  33 = p P U0304 U0304 U0304 U0304
 keycode  34 = bracketleft braceleft U0331 U0331 U0331 U0331
 keycode  35 = bracketright braceright U0330 U0330 U0330 U0330
 keycode  36 = Return
 keycode  37 = Control_L
 keycode  38 = a A ae AE ae AE
 keycode  39 = s S ssharp ssharp ssharp ssharp
 keycode  40 = d D eth ETH eth ETH
 keycode  41 = f F thorn THORN thorn THORN
 keycode  42 = g G
 keycode  43 = h H sterling sterling sterling sterling
 keycode  44 = j J EuroSign EuroSign EuroSign EuroSign
 keycode  45 = k K
 keycode  46 = l L
 keycode  47 = semicolon colon masculine ordfeminine masculine ordfeminine
 keycode  48 = apostrophe quotedbl currency currency currency currency
 keycode  49 = grave asciitilde dead_grave dead_tilde dead_grave dead_tilde
 keycode  50 = Shift_L
 keycode  51 = backslash bar section section section section
 keycode  52 = z Z
 keycode  53 = x X
 keycode  54 = c C ccedilla Ccedilla ccedilla Ccedilla
 keycode  55 = v V
 keycode  56 = b B
 keycode  57 = n N ntilde Ntilde ntilde Ntilde
 keycode  58 = m M mu mu mu mu
 keycode  59 = comma less guillemotleft guillemotleft guillemotleft guillemotleft
 keycode  60 = period greater guillemotright guillemotright guillemotright guillemotright
 keycode  61 = slash question questiondown questiondown questiondown questiondown
 keycode  62 = Shift_R
 keycode  63 = KP_Multiply XF86_ClearGrab
 keycode  64 = Alt_L Meta_L
 keycode  65 = space
 keycode  66 = Caps_Lock
 keycode  67 = F1 XF86_Switch_VT_1
 keycode  68 = F2 XF86_Switch_VT_2
 keycode  69 = F3 XF86_Switch_VT_3
 keycode  70 = F4 XF86_Switch_VT_4
 keycode  71 = F5 XF86_Switch_VT_5
 keycode  72 = F6 XF86_Switch_VT_6
 keycode  73 = F7 XF86_Switch_VT_7
 keycode  74 = F8 XF86_Switch_VT_8
 keycode  75 = F9 XF86_Switch_VT_9
 keycode  76 = F10 XF86_Switch_VT_10
 keycode  77 = Num_Lock Pointer_EnableKeys
 keycode  78 = Scroll_Lock
 keycode  79 = KP_Home KP_7
 keycode  80 = KP_Up KP_8
 keycode  81 = KP_Prior KP_9
 keycode  82 = KP_Subtract XF86_Prev_VMode
 keycode  83 = KP_Left KP_4
 keycode  84 = KP_Begin KP_5
 keycode  85 = KP_Right KP_6
 keycode  86 = KP_Add XF86_Next_VMode
 keycode  87 = KP_End KP_1
 keycode  88 = KP_Down KP_2
 keycode  89 = KP_Next KP_3
 keycode  90 = KP_Insert KP_0
 keycode  91 = KP_Delete KP_Decimal
 keycode  92 = ISO_Level3_Shift
 keycode  93 =
 keycode  94 = less greater bar brokenbar bar brokenbar
 keycode  95 = F11 XF86_Switch_VT_11
 keycode  96 = F12 XF86_Switch_VT_12
 keycode  97 =
 keycode  98 =
 keycode  99 =
 keycode 100 =
 keycode 101 =
 keycode 102 =
 keycode 103 =
 keycode 104 = KP_Enter
 keycode 105 = Control_R
 keycode 106 = KP_Divide XF86_Ungrab
 keycode 107 = Print Sys_Req
 keycode 108 = ISO_Level3_Shift
 keycode 109 =
 keycode 110 = Home
 keycode 111 = Up
 keycode 112 = Prior
 keycode 113 = Left
 keycode 114 = Right
 keycode 115 = End
 keycode 116 = Down
 keycode 117 = Next
 keycode 118 = Insert
 keycode 119 = Delete
 keycode 120 =
 keycode 121 =
 keycode 122 =
 keycode 123 =
 keycode 124 =
 keycode 125 = KP_Equal
 keycode 126 =
 keycode 127 = Pause Break
 keycode 128 =
 keycode 129 =
 keycode 130 =
 keycode 131 =
 keycode 132 =
 keycode 133 = Super_L
 keycode 134 = Super_R
 keycode 135 = Menu
 keycode 136 =
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 keycode 194 =
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 keycode 196 =
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 keycode 198 =
 keycode 199 =
 keycode 200 =
 keycode 201 =
 keycode 202 =
 keycode 203 = Mode_switch
 keycode 204 = NoSymbol Alt_L
 keycode 205 = NoSymbol Meta_L
 keycode 206 = NoSymbol Super_L
 keycode 207 = NoSymbol Hyper_L
 keycode 208 =
 keycode 209 =
 keycode 210 =
 keycode 211 =
 keycode 212 =
 keycode 213 =
 keycode 214 =
 keycode 215 =
 keycode 216 =
 keycode 217 =
 keycode 218 =
 keycode 219 = multiply division ISO_Next_Group ISO_Prev_Group ISO_Next_Group ISO_Prev_Group
 keycode 220 = XF86Search
 keycode 221 = XF86Meeting
 keycode 222 =
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 keycode 235 = XF86Display
 keycode 236 =
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Now, all arrows keys can be used, but the Up one. Go into KDE Control Center. In the Regional & Accessibility/Input Action pane, look for the Preset Action/PrintScreen. In the General tab, click on the Disable check box.