> -----Original Message-----
> From: Brian Donaldson [mailto:[log in to unmask]]

[reordering slightly...]
> 2) Is it an LDEV ?

A "(L)ogical (DEV)ice".  From the HP's point of view, I/O activity from/to the "real world" occurs on "logical" devices which are in turn mapped to "real" devices such as terminals and printers.  (tapes and disks also figure into this for "persistent" storage)  Another way to say this is that "a logical device provides an internal representation of a physical I/O device for access by programs and the OS."

Generally the mapping is one-to-one: your boot disk, for instance, is (usually) the first DISC drive on the first SCSI channel, so it gets mapped to "logical" device 1 [though "the first disc" might actually be at SCSI address 6 if I recall correctly...]  Other devices have historical assignments: the "printer" is LDEV 6 [think "Fortran"], the first tape drive is 7 [again fortran, I think...] and the card-reader is LDEV 10 [umm "spooled input device for jobs anyone?"]  After that, "terminals" usually began at LDEV 20 [the console] and went from there.

However, some physical I/O channels provide multi-cast access (think "networking") so the system may allocate several "logical" devices that essentially "fill in the gaps", which is why you might have people "logging on" to LDEV 3, 4, 5, 8, 9, 12 [ldev 2 would be a second disk drive, and 11 was typically allocated to the 1/4" (tape) cartridge drive]

> 1) What is a port?

Depending on your terminology background, a "port" could be an LDEV [if you are completely HP minded] or it can be part of the (TCP) network protocol [umm, "just about everyone else" ;) ]  Going with the latter, a "port" is a two-byte value used to differentiate a conversation/channel in TCP/IP networking.  The "IP" address of a computer is a 4-byte value, which is often analogized as "the phone number of a building", and the "port" is the specific service you wish to connect to at that address [again, in a building analogy, a "port" would be an office extension on the phone network]

> 3) Why would I want to open a port?

Programmatically, you "open a port" to establish a connection with a server.  In a network administration role, you "open a port [on a firewall]" to allow traffic "from the outside" of your network to access a specific server on the inside of your network.  "ports" in this case refer to TCP/IP ports, not HP Ldevs

> 4) If someone on a pc client machine (Windows etc) is trying to
>    sign onto the HPe3000 do they come in thru a port that is 
> open or ???

Depends on the connection -- if they are connected to a DTC, they would be using a serial "port" [ooops, another definition needed: a physical I/O channel on a PC...] to connect to the DTC and this has NOTHING to do with TCP "ports" [or firewalls...]  However, because you are asking [and I presume "have been asked..."] this question, I presume you're talking about TCP "ports" :)

The HP has two primary methods of allowing a connection "from a network" to occur: VT and Telnet [sorry, no SSH]  "Telnet" has been assigned "port" number 23 by the Internet Access (?) Naming Authority [a group of guys who thought this stuff up in the first place -- look for "IANA" and see also "RFC"] and this is what provides "standard command line access" to the server [also called "the colon-prompt"]  VT is HP's variant specifically for MPE and uses [I believe] port 1533 or thereabouts (I think there is a secondary VT "port" also)

Other "ports" that can be used to access the HP are FTP [20], HTTP [80], and "anything else you can write a server for..."

So to REALLY answer that last question [which is the real question here, I believe] the following has to occur:

   1) the PC needs some form of "client" to access the HP -- this would be a "termulator" such as Reflection, Miniterm, QC-term, <something home grown>, Hyperaccess, the supplied-with-windows "telnet" client, or similar.
   2) the PC needs a network connection to the HP [either from "within" a firewalled environment, or "through" a firewall]
   3) the HP needs to be "listening" for these connections (which means for the dedicated-to-hp3000 termulators of reflection, miniterm, and qc-term, this would be VT -- everything else would need "telnet")

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