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Proper Serial Console Support
I snarfed this from Daily DaemonNews, and it's very cool. If you administer a bunch of PC Unix servers (BSD, Linux, whatever) you probably miss the serial console that proper servers have. Once the OS is booting you can get serial output, but that doesn't help for modifying the BIOS. For that you need a monitor and keyboard. Enter the PC Weasel, an ISA board that pretends to be an MDA card, but actually stuffs the display out a serial port, and takes keyboard input and plugs it in to the keyboard buffer. So no need for a monitor now, just a serial connection. Probably the best thing is that if you buy one, you automatically get a source license for the microcontroller code, so you can customise it all you want.
BTW, this is a followup to the Ask Slashdot about KVM switches: disregard whatever it ways in there and just buy the Blackbox. A lot of people said the Linksys units were OK, but I had nothing but trouble. Replaced it with the Blackbox and it's all joy. Someone said the Blackbox is a re-badged Cybex (and we don't need no steenking badges), but I couldn't verify which one, so I just bought the Blackbox, and it's sweet.
What advantage did you imagine the extra expense of custom engineering would bring?
Consider a rackmount situation where the card must fit in a very small case. Height makes a BIG difference there. In a 1U case, the card will be mounted horizontally, making the height matter even more.
And for the random cases where your BIOS has been scrambled by interplanetary nuclear forces, grab the monitor off the desk...6 feet away (!).
Given my servers' location, it will take me no less than an hour (travel time) to grab a monitor off the desk and plug it in. Add to that that servers NEVER go down at nice convieniant times like Wednesday at 2:15 PM, it's always 3:00 AM Sunday morning during a thunderstorm when the car won't start (in 6 feet of snow, uphill both ways with the blazing sun burning down on you). It's much nicer to dial in to fix those problems. It also gets the system up faster or at least provides a clue as to what spare parts it will need.
In a datacenter environment, you don't want to go lugging a monitor around. Besides, if you don't know what's wrong with a machine, you don't go turning the thing off just so you can plug a keyboard into it! And yes you could have a keyboard attached to each machine but that gets a little annoying when you've got a few hundred or thousand machines.
_damnit_
_damnit_
It's my job to freeze you. -- Logan's Run
I set up a little mini-distribution of Linux, called "Serial Terminal Linux" that allows you to use an old laptop as a serial console. A single boot floppy puts you directly into Minicom. You can get it athttp://members.wri.com/johnnyb/serialli nux/. Very useful. I configure servers at a desk that I don't want a monitor taking up space on, so I just use a little laptop. Works wonders.
Engineering and the Ultimate
BREAK
At least that's what I use with our Intel N440BX servers. (Yes, some things never seem to change; using BREAK in this way dates back to Teletype days.)
Assuming this is the only ISA card in your system (pretty likely on a server), none of the issues you raise are relevent. It doesn't do DMA, its IO needs are small, it doesn't need PnP, it isn't going to need to share IRQ's, parity is a non-issue, and why should the fact that it's a 5V bus make a bit of difference? All the problems you mention would be genuine issues in many other circumstances--but not this one. Once your server is actually up and running, the only thing this board draws from the bus is power. Prior to that, its performance falls squarely in the "good enough for the purpose" category.
It's a sign of a green engineer to reject a solution on irrelevent technical grounds. There are legitimate reasons to reject an ISA solution--such as the fact that newer server boards don't even support it--but the factors that make it a crappy bus for almost any other purpose just don't apply here.
Have you ever worked in a data center environment?
What you should be envisioning here is not "a seperate serial terminal for each server".
You should be envisioning "a terminal server hooked to a bunch of servers, and you telnet into it".
That's one of the tools we use in data center environments, and it's been tried and tested and proven as a good solution for decades.
Even for small environments, if you have never worn out a video port or a keyboard port then you haven't done enough of your proposed solution to really comprehend the problems inherent.
I'd far rather buy a cheap multiport serial card for my main workstation at home and hook my other boxes up to it than futz around with KVM switches or moving cables around.
PC connectors aren't built to be used that much. It's a fact. That's why enterprise hardware doesn't use those connectors.
Why not. I used to have a 3COM Ethernet bridge that supported RS-232 and telnet for the console terminal. It needed a terminal connected to the serial port for initial setup but everything after that could be done by telnet.
Mea navis aericumbens anguillis abundat
That doesn't make it any less useful if you are stuck with a machine that doesn't have serial BIOS support.
I hope, however, that PC vendors will start to adopt the (open firmware standard). People are working on an open source implementation for PCs.
Bah.
The last NT Admin is no longer employed in the CC
of the university, but he's still around, since
he is a postgraduate student. He was wondering
why he couldn't login and dropped in.
I'll remember to post a full description of the
organization I work for and a staff list next
along with a short list of recent changes next
time I post. Not.
-W
Er... that was the only NT box in the computer room, and we no longer employ an NT Administrator (NT Administrator? isn't that an oxymoron?) - hence that box was noone's responsibility. I took the responsibility, and replaced it with something manageable that actually works without the need for a trained monkey to go around rebooting the damn thing every now and then. As an added bonus, I used an old vt420 (we have shitloads of them gathering dust downstairs) to replace a perfectly good 17" monitor that was wasted on a goddamn server.
I guess it must suck to work for you.
-W
This glitch is well known, but there is a fix. Take a look at Sunsolve, (SRD B 20427). (Not sure if this is publicly available).
ooooooh! What does this button do? - DeeDee, Dexters Lab.
Actually I want the network version. I want to be able to telnet into it, or better yet SSH in. PCI would be nice from a performance standpoint, but not needed.
Provided you can telnet in. The "watchdog" daemon, as I call it, would only require a telephone to reboot the computer. I should point out that Ctrl-Alt-Delete requires the use of a daemon as well. (The original poster wanted to send a three-finger salute via a serial line).
Of course, if daemons are not available and the system really is hung, there are still a couple of options. You could have the power supply hooked up to an X-10 device that is designed to be operated remotely by telephone, for instance.
My journal has hot
First, as an earlier poster pointed out, it's ISA only, not PCI (and server-class motherboards supporting ISA are quickly becoming extinct).
:P
:) called watchcat or watchdog or something like that ... and what it would do is sit in the background, waiting for your modem to ring. If your modem rang a set number of times (I set mine to 4 rings), then it would reboot the computer. And since the modem, is after all, connected to a serial line, voila! three finger salute via serial line. :) (Ok, so I'm a smart ass :)
:)
Intel's C440GX+ motherboard has a single ISA slot...
Third, the last thing many of us who are maintaining machines with 1 or 2 rack unit heights is another card to try to fit in there. Some of us would like to use what little room we have for things like Gigabit Ethernet cards.
Get a bigger rack.
However, even serial console support isn't perfect. After all, how do you send the three-finger salute over a serial line?
This is actually possible! No, really. Back in the days when I was a BBS sysop (about 10 years ago), I ran a little TSR program (gawd, remember those?
I'd be willing to bet, though, that it would not be difficult at all to write a program such as this as say, a Linux/BSD/whatever daemon. Perhaps such a program even exists already (I never thought to look). Any takers?
My journal has hot
Oh absolutely, it would be quite useful, i.e., before the Linux kernel loads, for example, if there is a bad hard disk or the BIOS' CMOS memory gets erased.
:) then your screwed without this card.
However, if you don't normally have these sort of problems (yeah, right, Murphy loves computers), the capability of doing remote admin is built right into the Linux kernel. Just compile in the "Allow serial port consoles" or some such option, and make sure your init scripts set 'CONSOLE=ttys0' or whatever, and you're all set.
Of course, like I said, if you have boot problems before the kernel loads (oops, I recompiled the kernel remotely, rebooted and forgot to run 'lilo'
My journal has hot
I bet the VGA thing is what's causing Dells to freak out.
Why would anyone in their right mind make a new design based on the ISA bus ? This is a brain dead bus, without interrupt sharing and severe limitations on DMA and IO. There does not exist a complete specification on the bus, only a collection of random writings and books. There was an attempt by ieee (?) to make a spec, but they failed because of the ugliness of the existing implementations. It has an even more kludgey and unreliable plug and pray specification. The bus has no error correction, parity or ECC. I refuse to put any ISA card in any new computer (cheap home pc or desktop for the secretary), and this card is meant for servers !!
Oh, did I mention that the bus is +5V only ?
Oh well, back to work.
</rant>
RFC1925
Their block diagram shows one cable going to the keyboard and another going to the reset input.
It looks like you can give a hardware reset, not gust the nerve pinch.
telnet demo.realweasel.com
They said:
We know that it is possible to set a BIOS password and other annoying things but we ask that you be kind to the next person trying out the PC Weasel..
As you can guess, a sucker put a password. If he reads me, I can assure him that he's a childish looser.
Cheers,
--fred
1 reply beneath your current threshold.
Does anyone know if Intel will start supporting Forth toolkits (Open Boot in Sun world) with Itanium? If not, what do they plan on using?
If my post is screwed up, sorry.
_damnit_
_damnit_
It's my job to freeze you. -- Logan's Run
It contains an interview with Herb Peyerl, sometime NetBSD maven and the principal software designer, and some more photos.
But just a few off-the-cuff comments in response to previous posts:
- Herb mentioned the price to me a few weeks ago, and I already forgot - but it's in the very low hundreds;
- Custom ASICs weren't in the budget, that's for sure; cut them some slack, guys, they have to build a market first;
- The price will drop even before they get the huge volume required for custom ASIC chips; even a fair-sized production run will make a big difference.
- And as the web page itself points out, they really couldn't believe nobody else did this - they were finally driven to invent it themselves from need!
All this, and much more, in the interview.OK, a few weeks ago I noticed there was an NT
:)
box crashing along in our computer room, mostly
emmiting SMB traffic and broadcasting some radio
station via realaudio. I felt pitty for the poor
thing (dual PII-233, 256MB ECC RAM, pair of nice UW drives etc) and decided to install a real OS on
it.
Upon openning the case I realized it had an
on-board graphics card, albeit a sucky one,
so I discarded the ati rage pro that the nt
admin added. I then proceeded to install freebsd
on it from scratch. While I was tweaking the BIOS
settings (intel mobo, phoenix bios) I found an
option to redirect the console to a serial port
You should have seen the face of that NT admin
when he saw the box he setup a few months ago
attached to a vt420 doing what the NT box did and
outperforming it while at it.
I wonder why this is not more common - is it so
bloody hard for the BIOS to redirect the console
to a serial port? I don't think so. I really don't
like the idea of an add in board doing that for
you, it is a major kludge. Perhaps we should
make some noise to motherboard manufacturers
until they understand that serial console support
is a good thing, and it can be a selling point.
-W
I want an ethernet version! Who uses serial these days anyway? I suppose you could write your own microcode on one of these things to talk to an ethernet card??
-- Virtual Windows Project
I'm glad more people are beginning to realize that headless operation capability is a great asset to people who have to manage UNIX systems, and that having hardware support for such management is critical. Most UNIX systems vendors (such as Sun) have had this for years now.
However, my first impression of this card is "too little, too late."
First, as an earlier poster pointed out, it's ISA only, not PCI (and server-class motherboards supporting ISA are quickly becoming extinct).
Second, look at that card! It's frigging huge! It looks more like a FPGA prototype; I'm sure the designers could have it converted to a single chip ASIC and make the card 75% smaller.
Third, the last thing many of us who are maintaining machines with 1 or 2 rack unit heights is another card to try to fit in there. Some of us would like to use what little room we have for things like Gigabit Ethernet cards.
Finally, I'm not sure there will be much need for this in a few months. Award (now Phoenix) has a gorgeous ServerBIOS (which Intel is using on all of its new server motherboards) which supports serial console support. We're using one of their motherboards in all our new systems (I believe that VA Linux Systems uses them too) and we think they kick ass.
However, even serial console support isn't perfect. After all, how do you send the three-finger salute over a serial line?