[Tfug] Blameless Parts Trafficking

[erich]

Heh,
      I've been using a NEC8100, (Which I got from Worldcare, of course),
as an X-host. I installed an old version of SUSE in it. It has an old
version
of an x-server that doesn't have all the mind-boggling security features
that defeat the network-transparency of X. (Newer versions of the X-server
typically use SSH, but then a lot of my machines don't understand SSH)

      X- clients connect to it from all over my house: Including legacy DOS
machines, and the latest & greatest Gentoo machines.

                                                                 Erich

Bexley Hall wrote:

>WorldCare has several NCD Explora 401 X-terminals.
>These are definitely "an adventure in computing"  ;-)
>(I'm a strong advocate of diskless workstations even
>though their advantages are most evident in large
>organizations with dozens or hundreds of such
>terminals!).
>
>For more information, try:
>http://www.ncd.com/support/explora/400/
>
>Physically, these are about the size of a small,
>hardback book -- about 6" x 10" x 2".  They are
>usually shown in their funky stand -- which holds
>them "standing on edge" (i.e., 6" *tall*, 2" wide,
>10" deep) to minimize their footprint on the desktop.
>
>Connections to the monitor, keyboard and mouse
>resemble those of a (PS/2) PC.  A keyboard and 3
>button mouse come with the unit -- you supply
>the "VGA" monitor.
>
>Any multisync "VGA" monitor should work.  The terminal
>can be configured in a variety of display resolutions
>up to 1152x900.
>
>Power is from a wall wart.  Since the device only
>consumes ~20W, there is no fan.  Since it is diskless,
>there is no rotating media.  Together, this means
>*silent* operation!  Attach an LCD monitor and you've
>got a low power, small footprint "console" suitable
>for use in a bedroom or quiet office -- away from all
>the noisey servers!
>
>"CD quality" stereo audio is available from a 1/8"
>jack.  There is also a tiny speaker inside the
>terminal for beeps and bops -- though it is also
>accessible via nasd(1) (the folks at NCD developed 
>the NAS protocol).
>
>A single PCMCIA slot.
>
>A serial port (DB9) and a parallel port (DB25).
>
>Comes with 8MB of DRAM (?) though this can be
>expanded to 64M (I've seen claims of 128M capacity
>but have never actually *seen* a 64M 72 pin SIMM)
>using 60ns FPM or EDO 72 pin SIMMs (QTY 2).
>
>The drawbacks (some are inherent in diskless
>workstations, some specific to X terminals and others
>a consequence of this particular *design*) are
>primarily:
>- only an 8-bit deep display (i.e., only 256 colors
>  in the colormap at any given time).  However, the
>  color *palette* (CLUT) appears to be 24 bits deep.
>  So, you won't notice any degradation on most
>  photographs.  But, switching between clients (aka
>  applications... "windows") can result in colormap
>  "flashing" (the color map of the focused window
>  gets loaded which means the "logical colors"
>  currently in use in some *other* window may no
>  longer be available -- so the contents of those
>  windows appear with bizarre colors while they do
>  not have the focus).
>- "only" an 1152x900 display (a small step down
>  from a 1280x1024 display)
>- network interface is 10BaseT.  You'll need a
>  dual-speed hub/switch if your other machines run
>  100BaseTX (or gigabit).  A more significant
>  consequence of this is the limitation it imposes
>  on display bandwidth.  If you're looking to
>  display full screen "movies" or *games*, you'll
>  be disappointed!  You don't have that big fat 
>  *pipe* (e.g., AGP video) from the application
>  (i.e., CPU) to the display!  OTOH, if you are
>  a "typical" computer user browsing web pages,
>  text, etc. you shouldn't feel constrained -- even
>  if you're an adherent of one of the "bloated
>  desktops"!  :>
>- there is no audio *input*.
>- the PCMCIA slot is only (??) useful for a flash
>  memory card to optionally store the bootstrap image
>  (and fonts, etc.) on a "local filesystem".
>- "security" can be an issue *whenever* you exploit
>  the ability of running an X Windows display remotely
>  (since lots of traffic appears "on the wire"
>  unencrypted).
>
>The most *practical* downside of X terminals is the
>level of expertice required to get them running.  :<
>But, I can offer some help, here.  (I've been using
>X terminals for more than a decade)
>
>NCD terminals (I've played with about 6 different
>models and all seem to follow the same gameplan) have
>a variety of configuration options (can you spell
>"kitchen sink"?).  I've settled on the following
>scenario:
>- power up the X terminal (and monitor)
>- the terminal broadcasts a BOOTPc request
>- a BOOTPs reply tells the terminal its:
>	. IP address
>	. netmask
>	. IP of DNS
>	. name (and location) of boot file 
>	. name (location) of configuration file
>- X terminal downloads its boot file from TFTP server
>- boot code in the X terminal mounts NFS partitions
>  from a remote file server to access its:
>	. configuration file
>	. font files
>- X terminal downloads configuration files and fonts,
>  as needed and *when* needed (i.e., if you invoke the
>  "setup" menus on the X terminal and alter its
>  configuration, the changes are *written* back to
>  that configuration file)
>- X terminal broadcasts an XDMCP request to identify
>  hosts to which it can connect (actually, hosts that
>  can connect to *it*!  :> )
>- X terminal presents a list of hosts that
>acknowledged
>  its XDMCP request (i.e., hosts into which you can
>  login)
>- user picks a host from this list
>- that *host* (running xdm, or some bastardization
>  thereof) presents a login dialog to the user
>- user specifies login name and password
>- once logged in, xsm(1) presents a lost of "saved
>  sessions" for the user to chose among (yuck! crappy
>  grammar there  :< )
>- user picks a session from this list -- or, a "fail
>  safe" session (typically just an xterm and window
>  manager)
>- xsm(1) restarts registered applications for that
>  session
>- user runs any other clients (applications) as
>  desired
>- when done, user logs out
>- the process then repeats with the issuance of
>  another XDMCP broadcast
>
>As you can see, the X terminal requires services of
>external hosts to operate:
>- BOOTP server for initial configuration
>- DNS server to resolve names
>- TFTP server for boot image
>- NFS server for configuration files and fonts
>- optional "font server" (i.e., xfs(1))
>Plus, the host (or hosts!) to which the X terminal
>will ultimately *connect* for clients/applications
>(e.g., xdm(1)).
>
>However, these services can all be provided on a
>single host (e.g., I run them all on an old Sun SS5
>tucked in a corner of my office -- as well as running
>xdm(1) on that same SS5 so that *it* can act as a
>"host"!).
>
>Also, there are *so* many configuration options that
>allow a variety of different environments to be
>supported.  For example, the TFTP and NFS roles can
>be reversed.  Or, lumped into a single service (i.e.,
>entirely using TFTP or entirely using NFS).  Or, use
>MOP for you DEC-heads.
>
>rarpd(8) or dhcpd(8) can replace bootpd(8) for
>terminal
>identification.  xfs(1) is only required if you are a
>fontaholic.  DNS can be replaced by a static list of
>(name,IP) bindings (i.e., similar to hosts(5)).
>
>Or, the process can be canned in NVRAM (i.e., "hard
>code" the terminal's name, IP, etc.).  A flash card
>can be used to store the boot image and fonts
>"locally" thereby eliminating *all* of this overhead.
>
>The terminal has other capabilities once booted (i.e.,
>at the point where it is ready to broadcast its XDCMP
>request).  You can, for instance, open a telnet
>session
>directly from the terminal to any other IP-accessible
>host (*without* the intervention of any other hosts).
>Or, connect directly to the serial port (i.e., you can
>have a "window" that behaves as a conventional
>"terminal"/"glass TTY").  I use this feature to give
>me a free "serial console" for my Sun machines.
>
>Aside from the centralized maintenance aspect (which
>is what makes X terminals such a *win*, IMO, for a
>business), they are ideal for use with headless
>servers.  For example, I run all of my machines
>headless (I don't want to waste space on monitors and
>keyboards and mice for each of them).  I can then
>sit someplace comfortable (and *quiet*) and access
>any of the machines (even concurrently) without having
>to be near the machine in question -- exploiting X
>Windows to give me a sort of "networked KVM"...
>
>There are a fair number of these units at WorldCare,
>currently.  They are asking $10 for each kit (mouse,
>terminal, keyboard and wall wart).  They are quite a
>fun challenge to get running -- as well as *use*!
>
>Hopefully I've covered all the *major* issues for
>those folks who've never played with such beasts...
>Sorry for the lengthy post!  Feel free to ask (here,
>or off-list) if something isn't quite clear.  It 
>would be a shame for these things to get scrapped :-(
>
>We now return you to your regularly scheduled
>broadcast...
>
>--don
>
>
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