• comp.sys.3b1 FAQ part2

    From jbunch@jbunch@nyx1.nyx.net (John B. Bunch) to comp.sys.3b1,comp.answers,news.answers on Wednesday, November 12, 2003 16:33:49
    From Newsgroup: comp.answers



    Archive-name: 3b1-faq/part2
    Version: $Id: 3b1-faq-part2,v 2.5 2000/09/05 19:17:48 jbunch




    ----------------------------------------------------------------------
    | Answers to some frequently asked questions about the AT&T UNIX PC, |
    | as well as some frequent problems, hints, and solutions. | ----------------------------------------------------------------------
    | Make a Hard Copy on the FAQ *NOW*, it probably wont be readable if |
    | it is on your machine when you *NEED* it. | ---------------------------------------------------------------------- [$Revision: 2.5 $ $Date: 00/09/05 19:17:48 $]
    Send updates to 3b1-faq@nyx.cs.du.edu.

    Part 2 of 2

    ------------------------------

    Subject: 0.2. Table of Contents for part 2 of the faq.

    0.2. Table of Contents for part 2 of the faq.
    5.0. Upgrading continued.
    5.3. Can I really get 4MB of memory, even with a 1.5MB combo
    card, 512K RAM card, and 2MB of RAM on the motherboard?
    5.4. What dynamic memory chips can be used to upgrade a
    3b1/7300?
    5.4. Can I hook up a 3.5" 720K floppy drive to my UNIX PC? How
    about a 1.2MB or 1.44MB floppy drive? Can I run both the
    3.5" drive and the 5.25" drive on my machine somehow?
    5.5. Can I put a larger hard disk drive in the UNIX PC?
    6.0. Maintenance
    6.1. How do I park the hard disk heads before moving the machine?
    6.2. How do I open the case and get to the motherboard?
    6.3. Why does my fan sometimes speed up and slow down? Should I
    replace it?
    6.4. Why has my clock stopped?
    7.0. Failures
    7.1. What can I do when I turn on my UNIX PC and all I see is
    a "green screen"?
    7.2. What can I do when I turn on my UNIX PC and I have no
    video?
    7.3. What can I do when I get lots of FDERRs when
    writing/formatting a floppy?
    7.4. Why does rn fail with "Can't open /dev/tty" from the
    built-in modem?
    7.5. Can I connect my Starlan board to an Ethernet?
    7.6. Can I run SLIP (Serial Line Internet Protocol) on my UNIX
    PC?
    7.7. What are the consequences of "fsck -s" (salvaging the
    freelist)?
    7.8. What does the "-s" option to dismount do?
    7.9. How do I identify what motherboard revision I have?
    7.10. How can the monitor fail?
    8.0. Mysteries
    8.1. What are the LED's left side of the machine for?
    8.2. What's /etc/update? What does it do?
    8.3. Why did the time display at the top of the screen go away?
    8.4. How do I stop that darn double-ESC mode on console windows?
    8.5. What do I do when the machine hangs at the boot message?
    8.6. How can the UNIX PC be made more secure?
    8.7. How do I access the expert menus in the diagnostics?
    9.0. Credits

    ------------------------------

    Subject: 5.0. Upgrading continued.

    This is a continuation of the upgrading section from part 1 of the faq.

    ------------------------------

    Subject: 5.3. Can I really get 4MB of memory, even with a 1.5MB combo
    card, 512K RAM card, and 2MB of RAM on the motherboard?

    The answer is yes. It does require a simple pin-ectomy. You
    need to fool the hardware to think the 512K RAM card is in a slot that
    doesn't physically exist on the UNIX PC. For more information on how
    to do this, grab John Milton's HwNote06 from the archive sites.

    ------------------------------

    Subject: 5.4. What dynamic memory chips can be used to upgrade a
    3b1/7300?

    The following is a cross-reference list of 256 by 1-bit dynamic
    memory chips that are usable for 3b1/7300 memory upgrades:

    AM90C256-xx AMD Advanced Micro Devices
    MB81256-xx FUJ Fujitsu
    HM50256-xx HIT Hitatchi
    HY53C256-xx - Hyundai
    P21256-xx - Intel
    M5M4256P-xx MIT Mitsubishi
    MCM6256-xx MOT Motorola
    UPD41256-xx NEC NEC Technologies
    MSM41256-xx OKI Okidata
    KM41256-xx - Samsung
    TMS4256-xx TI Texas Instruments
    TMM4256C-xx TOSH Toshiba

    The digits in xx are speed designations--common values are:
    xx=10 for 100ns; xx=12 for 120ns and xx=15 for 150ns.

    Since it is now economically advantageous to obtain chips from
    third parties (private sales, auctions or hamfests), the
    manufacture's LOGO and identification stamped on the chip may
    be the only clues one has for a scavenger hunt. If the
    experimentalist is not familiar with the Manufacture's LOGOs,
    a perusal of a computer magazine (PC World, etc.) should
    help one to become familiar with most of them. Good hunting!

    ------------------------------

    Subject: 5.5. Can I hook up a 3.5" 720K floppy drive to my UNIX PC? How
    about a 1.2MB or 1.44MB floppy drive? Can I run both the 3.5"
    drive and the 5.25" drive on my machine somehow?

    Yes, to the 720K. No, to the 1.2MB and 1.44MB.

    Putting a 720K 3.5" floppy drive is rather simple if you are
    just replacing the existing 360K 5.25" drive completely. In most
    cases it's a one-to-one swap, providing you can get the jumper setting
    set correctly on the 3.5" drive.

    You can run both drives, provided you make a mechanical switch
    (SPDT) to change the drive select between the 5.25" 360K internal
    drive and the 3.5" 720K (run externally). You need to make a cable to
    switch the pin 10 (FDRIVE0*) from one drive to the other. Drilling a
    hole in the case above the left fan grate is a suitable spot.

    When you use the 720K drive, all you need to do is create an
    iv description file that has 80 cylinders instead of 40, and you get
    the full 800K (80 tracks, 10 sec/trk). Makes backups go faster!

    ------------------------------

    Subject: 5.6. Can I put a larger hard disk drive in the UNIX PC?

    Upgrading from a 10MB, 20MB, or 40MB to a 67MB drive requires
    a 3B1 power supply and a 3B1 case top (the 40MB and 67MB drive is
    full-height). There are other solutions to this -- you can get
    half-height drives that have seek times faster than the 80ms of the
    old 10MB and 20MB drives, and which have more disk space. So long as
    the drive has a ST506/MFM interface, has less than or equal to 1024
    cylinders and less than or equal to 8 heads, the drive will work
    without *any* hardware modifications.

    To upgrade to a disk with more than 8 heads and more than 1024 cylinders there are several approaches one can take. Gaining more
    cylinders is the easiest of upgrades: all you need to do is replace
    the WD1010 disk controller (which is socketed on the motherboard at
    location 21H) with the pin-for-pin compatible disk controller, WD2010.
    The WD2010 comes in several varieties, and all seem to work for the
    most part (WD2010A, WD2010B, etc.). The WD2010 is a very difficult
    part to come by -- Intel makes (or made) a pin-compatible version of
    the WD2010, the Intel 82064. There has been some discussion on Usenet
    that people haven't been able to get the WD2010 to work in their older
    revision motherboard UNIX PC or PC7300. These machines have a
    daughterboard that handles the disk circuitry, instead of the
    all-in-one chip that was replaced in the later models.

    The operating system, from at least release 3.0, supported an unreleased motherboard revision, P5.1. The P5.1 revision level (like
    the P3...P5 that you see during the boot phase) includes some extra
    features such as an extra disk head select (expanding to 16 read/write
    disk heads) and extra drive select (allowing expansion to two
    simultaneous hard disks). With the appropriate hardware modifications
    (all requiring some expertise in soldering and reading schematics),
    one could upgrade his motherboard to emulate this undocumented
    motherboard revision. These upgrades weren't released to the public
    by either CT or AT&T during the life-cycle of the product, but were
    later released and made public by several people in several different
    forms.

    o John Milton <jbm@megalinx.net> has a prebuilt circuit board that
    offers up to 4 hard disks and 2 floppy drives, but be forewarned
    that the operating system only supports the two hard disks and
    one floppy drive. If the operating system patches could be made,
    John's hardware would support it. He's offering a prebuilt and
    pretested board that can be wired into the motherboard.
    The motherboard wiring (jumpers) and soldering will have to be done
    as well before you can use John's board (this is not a plug in and
    go situation -- it requires some time to wire). The board and
    instructions currently cost $75, but contact John for pricing.
    [As far as I know this is no longer available from John]

    o SSDL/ICUS Hard Disk Upgrade Version 2.0.
    Gil Kloepfer, Jr (gil@limbic.ssdl.com) is currently (10Jan92)
    offering the second version of the popular ICUS do-it-yourself
    hard-disk upgrade kit. From the announcement, answering the
    question "What is it?" --
    "It is a single-chip upgrade to the 3B1 that allows a second
    hard disk to be added and a 4th head select line to allow
    disks with more than 8 heads to be used. It is a superset of
    the functionality of the P5.1 PAL (ie. you don't need P5.1 to
    use the V2.0 PAL), and completely emulates all the
    functionality of the earlier ICUS V1.0 upgrade.

    "This upgrade *DOES NOT* extend the number of cylinders
    1024). You must purchase a WD2010 to replace the WD1010
    chip on the motherboard if you wish to do this."

    Full information about availability and pricing can be
    obtained from v2upgrade@limbic.ssdl.com.
    [This is also no longer available from Gil *See Below*]

    [The following was received from Gil]
    Just letting you know that the WWW page with the HD upgrade
    instructions and the PAL equations is up and operational. My
    apologies in advance that the formatting is basic and the
    diagrams are scanned-in and put up as GIF images. I'm sure
    those who need the info will be grateful anyhow.

    The URL is: http://www.gc2.kloepfer.org/~gil/hdinstr.html

    There is no other pointer anywhere around to this location, so
    if there is some kind of 3B1 web site, it should likely be
    referenced there.

    Enjoy! If you see any glaring mistakes, send an email to
    "Gil Kloepfer Jr." <gil@gc2.kloepfer.org>.

    o FIELD P5.1 PAL upgrade. The P5.1 instructions were posted to
    unix-pc.general a long time ago, and are now archived on OSU in
    the P5.1.Z file. This requires a preprogrammed PAL chip to be made.

    The largest disk which can be handled by the UNIX PC/3B1 is:

    o Motherboard revision P3...P5 (WD1010 disk controller)
    8 heads x 1024 cyls x 16 sectors/track x 512 bytes/sector = 67.1MB

    o Motherboard revision P3...P5 (WD2010 disk controller)
    8 heads x 1400 cyls x 16 sectors/track x 512 bytes/sector = 91.7MB

    o Motherboard revision P5.1 (modified) (WD1010 disk controller)
    16 heads x 1024 cyls x 16 sectors/track x 512 bytes/sector = 134.2MB

    o Motherboard revision P5.1 (modified) (WD2010 disk controller)
    16 heads x 1400 cyls x 16 sectors/track x 512 bytes/sector = 183.5MB

    NOTE: 1400 cylinders is the #define HDMAXCYL in /usr/include/sys/gdisk.h -- although the WD2010 can support up to 2048 cylinders, the operating system cannot. Also, with the multiple hard
    disk upgrades you can have two disks that can be as large as the above
    sizes for the P5.1 modified motherboard revision.

    FINAL NOTE ON THE WD2010: Some folks have reported troubles
    with their systems after installing the WD2010, far too many to
    discount as due to bad chips. Thad Floryan was irritated enough by
    this to take time away from sheep-herding and solve the problem. This
    problem occurs only on certain versions of the 3b1 motherboard.
    Short and sweet, quoting from Thad here:

    "So, in overview, the complete and correct "DRUN patch" modification
    to a 3B1 motherboard which does function with a WD1010 but does not
    function with a WD2010 is:
    1. separate and lift [13N] 74123's pins 1 and 2
    from the motherboard
    2. run a wire from the lifted [13N] pin 1
    to [13M] 74F10 pin 7 (ground)
    3. run a wire from the lifted [13N] pin 2
    to [13K] 26LS32 pin 3
    4. replace R63 per:
    original: 6.81K, 1%, 1/4W
    new value: 4.75K, 1%, 1/4W
    Parts list:
    1. new 74123 (reason for this is described below)
    2. 4.75K, 1%, 1/4 W precision resistor
    3. less than one foot of 30ga "wire-wrap" wire
    for the two patches"

    And additionally:

    "If your system is one that DOESN'T have the "DRUN Patch"
    then putting the WD2010 in your system will cause you a LOT
    of grief. From my observations on MANY systems, it's not
    always obvious whether the patch exists on one's system;
    some factory runs implemented the patch along the lines
    of what I described in my posting last December [excerpted
    above], and some runs had the patch integrated into
    (presumably) new motherboard layouts where the legs of the
    74123 chip are NOT sticking up in the air. If the resistor at
    R63 has the color code bands, then the presence of 4.75K 1%
    means the patch is already applied (the value of 6.81K 1%
    means you have the old data separator circuit which will NOT
    function properly with a WD2010); if the resistor is the RN05
    type (no color bands) then you probably won't be able to read
    the value and you'll either have to remove it (to read the
    value) or forget the whole thing.

    The ABSENCE of a capacitor at C252 is also a good clue one's
    motherboard has the DRUN patch already applied."

    ------------------------------

    Subject: 6.0. Maintenance

    This section answers general maintenance questions.

    ------------------------------

    Subject: 6.1. How do I park the hard disk heads before moving the
    machine?

    The Miniscribe and Hitachi disks used in the 40MB and 67MB
    machines parks the heads automatically (and loudly) when the power is
    turned off. (That's that *clunk* sound you hear when you hit the
    power switch.) Also note that many newer drives have auto-parking
    mechanisms -- check with your specific manufacturers for more
    information.

    If your drive doesn't auto-park (many Seagates don't), or you
    want to make extra sure that the heads are in the parked position,
    then after the machine is shutdown insert the Diagnostics floppy disk
    and boot from it. Select "Park Disk Heads" from the Diagnostics menu.

    Note that the older 7300 machines have 10 or 20MB disks which
    do not auto-park. If you're buying one used (especially at an auction
    or a fair), you may want to bring along a diagnostics diskette to make
    sure the disk is okay.

    ------------------------------

    Subject: 6.2. How do I open the case and get to the motherboard?

    [Courtesy of Norman Yarvin:]

    Three sets of screws hold the case together. The first set
    consists of two screws underneath the keyboard retainer posts, and
    three screws in the rear panel. (The keyboard retainer posts hold the
    keyboard to the base -- one is next to the socket for the keyboard
    plug. Note the seam around the top of the retainer posts. Remove the
    covers from the posts, and you'll find a screw inside each.)

    When this set of screws is removed, the top (plastic) part of
    the case is attached to the bottom only by some cables, which have
    enough slack to let you take the top of the case off, tilt it
    backward, and rest it on its rear behind the machine. However, this
    is quite a difficult task. This is because it is hard to get the very
    front of the case up; the plastic is shaped in such a way as to catch
    on to the metal bottom somewhere. A bit of wrestling with the case is
    usually necessary here, and some people prefer to take the top part of
    the top part off (the next paragraph) before taking off the bottom
    part of the top part.

    The second set of screws holds the top part of the case
    together. It consists of six screws, pointing upwards, which are
    found under the overhang of the case. The only time they really need
    to be removed is when replacing the fan. In addition to these screws,
    two or three plastic hook-and-tab latches in the front of the machine
    need to be released. The top of the case must be moved outward
    slightly (usually with a screwdriver or finger pressure) along the
    joint to the right of the floppy drive in order to release the
    catches. [The three plastic catches in the front are in the middle,
    and at about the 7th-to-10th louvers from the left and right of the
    case.]

    Taking off the top of the case exposes only the floppy drive,
    the hard disk (underneath shielding) and the power supply. To get to
    the motherboard, you then have to unscrew the third set of screws --
    three screws at the very front of the machine. The two latches on
    either side of the motherboard cover become obvious when one tries to
    lift up the panel, and are easily released. The motherboard cover
    pivots at the rear; it can be lifted up. To lift it up more than an
    inch, the power supply cable and the 10-pin video cable must be
    unplugged. After that the metal shielding can be lifted and slid
    along the tracks and then flipped up or removed. This exposes the
    motherboard. If you need to remove the motherboard shielding
    completely and the monitor assembly, you need to disconnect the floppy
    and hard disk cables from the motherboard (note the direction of the connectors, and when replacing them be very sure that the 20-pin and
    34-pin connectors are seated correctly on the associated pins). If
    you have a PC7300 power supply and motherboard, your floppy drive
    power cable might also be connected to the motherboard. To remove the
    whole assembly, in that case, you'll need to remove the power
    connector from the back of the floppy drive as well.

    Be careful when putting the top of the Unix PC/3B1 back on; a
    common cause for the machine not powering up after the cover is
    replaced is the 120VAC connectors (brown and blue wires crimped on)
    falling off the power input, or being pulled off by the hard drive as
    the case is closed. The green ground wire has a tendency to get
    caught in the fan blades (causing the fan not to start spinning when
    the machine is turned on) or caught in the case itself. Check that
    the fan is working after closing the case.

    As always, use your head. Be careful when exposing any
    component of the Unix PC. There are many static sensitive components;
    ground yourself before poking around inside.

    ------------------------------

    Subject: 6.3. Why does my fan sometimes speed up and slow down? Should
    I replace it?

    The fans have been a problem with the UNIX PC in a lot of
    cases. What happens is the 12VDC fan is connected to a thermal switch
    that will run the fan motor faster when the machine is hot, and then
    slow it down when the machine cools. There have been occasions,
    however, when a fan goes from fast to slow, and then slows all the way
    to a dead stop. The fan tends to collect a lot of dust and dirt, and
    sometimes when switching to the slow speed it goes so slow that it
    stops and doesn't have enough "umph" to start up again.

    Gil Kloepfer theorizes the reason for this happening is that
    the 12VDC fan is constantly running with too little current due to a
    resistor wired in series with the power supply when the thermal switch
    is in its normally open position. When the fan is beginning to
    malfunction, it will run subtly slower, but not enough to keep enough
    air moving through the machine. The thermal switch kicks-up the
    power, which causes the fan to move faster and cool the machine down
    until the switch kicks-out again. This cycling effect keeps going
    until the fan become excessively weak and clogged with dirt to where
    it eventually stops working permanently. But he goes on to add that,
    in any case, "I don't think it's just dirt."

    The next stage is the machine overheats, the power supply cuts
    out, and the machine powers down, then it powers up, and down, and up.
    If you are lucky, you catch this before major damage occurs or you
    take preventive measures beforehand. Most of the time the power
    supply gets so hot, it warps the plastic case above it. This is a
    sure sign that a UNIX PC has had a "meltdown" before.

    What can you do? Well, you can replace the 12VDC fan with a
    3" 120VAC fan. The 120VAC fans are more robust, they produce more air
    current (~34CFM normally) and don't draw on the power supply any. One
    drawback is that they are noisier. Radio Shack has an appropriate
    120VAC fan for $16.95, cat. no. 273-242.

    Some people can go years or forever without ever having a
    problem, but it just takes that one day that you aren't around and the
    machine goes into "meltdown" and then you'll be assured some damage
    somewhere.

    ------------------------------

    Subject: 6.4. Why has my clock stopped?

    Your battery is dead. On the UNIX PC motherboard there is a
    3.0 VDC lithium battery which keeps the real-time clock operating. Unfortunately, the battery is soldered to the motherboard in most
    cases. It's either the round cylindrical canister type, or more
    commonly the flat disc-shaped battery. A suitable replacement can be
    purchased at Radio Shack (BR-2325), but you'll need to get the disc
    battery holder. If you desolder the battery from the motherboard,
    solder in the holder, future replacement of this battery will be much
    simpler. If you are nervous about touching a soldering iron to your
    precious machine, ASCRC will do it for you (see above).

    ------------------------------

    Subject: 7.0. Failures

    This section answers question about failures.

    ------------------------------

    Subject: 7.1. What can I do when I turn on my UNIX PC and all I see
    is a "green screen"?

    This symptom crops up in a lot of UNIX PC's. Generally, the
    machine can be revived with only little fuss. Open the machine down
    to the motherboard. Carefully reseat all the socketed chips,
    especially the 68010 CPU. Blow all of the accumulated dust out of the
    machine (vacuuming is not recommended due to the possibility of static discharge). 7 times out of 10 the machine will boot afterwards. If
    the machine still doesn't boot, it could be something more serious.
    Check with the ASCRC on how you can go about getting the machine
    repaired.

    ------------------------------

    Subject: 7.2. What can I do when I turn on my UNIX PC and I have no video?

    The first thing you could do is check the brightness control.
    After you are sure that it's not that, the problem generally goes away
    by replacing the power supply. If you don't have a spare one, try
    asking on Usenet, or deal with ASCRC.

    ------------------------------

    Su
    ject: 7.3. What can I do when I get lots of FDERRs when
    writing/formatting a floppy?

    Jon H. LaBadie, Boyd Ostroff, and Perry Miller have suggested
    that there could be accumulated dust blocking the write protect
    apparatus on the floppy drive. The easiest solution for this is to
    get a can of compressed air, or blow real hard into the floppy
    aperture several times. This generally will remove the dust or dirt
    from the area, and hopefully will solve the problem. (With the light
    being blocked, the floppy drive is considered permanently write
    protected!)

    If the problem persists after you follow the simple solution,
    you might have to open the machine, remove the floppy drive, and
    perform a closer examination. If all else fails, a standard TEAC 360K
    floppy drive is a one-for-one replacement.

    ------------------------------

    Subject: 7.4. Why does rn fail with "Can't open /dev/tty" from the
    built-in modem?

    The problem is a line in the term.c file. The lines that have
    to be changed for rn to work are:

    Before change:

    [...]
    devtty = open("/dev/tty",O_RDONLY);
    if (devtty < 0) {
    printf(cantopen,"/dev/tty") FLUSH;
    finalize(1);
    }
    fcntl(devtty,F_SETFL,O_NDELAY);
    [...]

    After change:

    [...]
    devtty = open("/dev/tty",O_RDWR); /* changed for UNIX PC */
    if (devtty < 0) {
    printf(cantopen,"/dev/tty") FLUSH;
    finalize(1);
    }
    /* fcntl(devtty,F_SETFL,O_NDELAY); /* changed for UNIX PC */
    [...]

    This change is required because the /dev/ph* devices require
    DATA connections to be opened with O_RDWR, so changing the O_RDONLY
    (or, in some versions of rn, the constant 0) to O_RDWR will solve your problems. Note that these changes are also required for rn-derived
    programs like trn.

    ------------------------------

    Subject: 7.5. Can I connect my Starlan board to an Ethernet?

    No, you cannot connect Starlan to an Ethernet network, at
    least not directly. Starlan, or in the case of the UNIX PC, Starlan-1
    (1BASE5) is a 1Mbps (megabits/sec) network over twisted-pair wire.
    The URP protocol is used to communicate over Starlan-1 on the UNIX PC.
    The newer Starlan standard is Starlan-10 (10BASE2) and is 10Mbps which
    is more *like* Ethernet. The protocol used is the ISO/OSI standard,
    and therefore its interconnectability is increased. However, this is
    not compatible with the UNIX PC version. There is an expensive item
    that AT&T sells, called the Starlan 1:10 Bridge, which connects the
    two networks together if this is a necessity, but plan to spend around
    $4,500 for the convenience. (AT&T PEC Code: STARLAN 1:10 BRIDGE
    2611-005.) According to AT&T Stargroup documentation, there is
    software available to interconnect Starlan-10 hardware to Ethernet
    using IEEE 802.3, TCP/IP protocol, this of course in conjunction with
    the Bridge could connect Starlan-1 via the Starlan 1:10 Bridge to
    Starlan-10, and then to Ethernet, a roundabout way, but presumably
    possible.

    If you want to connect your UNIX PC to a *real* Ethernet,
    you'll need to hunt down the AT&T UNIX PC Ethernet board. This board
    runs a version of the TCP/IP drivers developed by Wollogong. The
    board will require the proper cables, as well as a transceiver. This
    increases the cost of Ethernet interconnectability. The Wollogong
    TCP/IP drivers are an older version not supported by Wollogong
    anymore. It's generally acknowledged that there are many bugs, and
    the throughput of the board is nowhere near what Ethernet should be
    getting. (People report that throughput with the Starlan-1 board was
    better than the TCP/IP Ethernet board, which shouldn't be the case.)

    Thanks to the hard work of Roger Florkowski (cs.utexas.edu!taliesin!roger), UNIX PC Starlan users don't have to be
    limited with just uucp'ing and cu'ing over the network. He has ported
    and created a bunch of BSD network utilities (r* commands). His
    package, (bsdslan.cpio.Z on OSU-CIS) allows one to do remote tape
    operations, remote copies, and remote shell commands.

    ------------------------------

    Subject: 7.6. Can I run SLIP (Serial Line Internet Protocol) on my UNIX PC?

    So far there hasn't been anyone who has ported a SLIP device
    driver. That would be the optimal solution, but in the interim we do
    have an answer for those who want to run SLIP.

    There is the KA9Q/W9NK TCP/IP Version 890421.1 available for
    the UNIX PC. Thanks to Phil Karn (the original developer), Gary
    Sanders, and Rob Stampfli, the package supports SLIP which in theory,
    over a modem or direct serial line (preferably 9600 baud or higher)
    one could use to connect to an Internet machine allowing Dialup/Direct
    SLIP logins. With the pseudo-tty driver (pty) you can have multiple
    TELNET sessions (even on the UNIX PC side). Built into the "net"
    package is FTP, TELNET, FINGER, SMTP, and others.

    KA9Q is available from OSU-CIS, Gary Sander's BBS or via
    anonymous uucp login on Rob's UNIX PC:

    kd8wk Any ACU 2400 16147598597 in:--in: uucp word: anonymous

    To obtain the net source, issue the following uucp command:

    $ uucp kd8wk!~/pub/netsrc.cpio.Z /usr/spool/uucppublic

    To obtain an executable for the AT&T 7300, enter the following:

    $ uucp kd8wk!~/pub/netexe.7300.Z /usr/spool/uucppublic

    System Name: N8EMR
    Phone: 614-895-2553 (19.2K Trailblazer, 2400, 1200)
    Login: hbbs
    Data Settings: 8 Bits, NO Parity, 1 Stop Bit
    Times: 24hrs

    ------------------------------

    Subject: 7.7. What are the consequences of "fsck -s" (salvaging the
    freelist)?

    Jim Adams sent some information regarding the uses (and
    dangers) of salvaging the freelist using the fsck(1M) command.

    fsck(1M) provides a method of salvaging and reconstructing the
    freelist maintained by the UNIX filesystem. It is dangerous to
    haphazardly do anything with the filesystem, as well as just
    reconstructing the freelist. If the filesystem isn't in a good state,
    it's possible that the freelist could be further damaged by just
    salvaging it. fsck(1M) will salvage the freelist when necessary, or
    when the question "SALVAGE (Y/N)?" is answered "yes".

    Jim has said that the alternative method, fsck -S, should be
    used if you wish to salvage the freelist. The salvage will only be
    done if the filesystem is properly constructed, and nothing damaging
    could occur by its reconstruction. If errors are found during the
    fsck phases, other than errors like "POSSIBLE FILE SIZE ERROR I=nnn"
    (which occurs from sparse files, also known as files with holes in
    them) the salvage will not be done.

    fsck(1M) is designed to be run on a mounted root filesystem,
    so long as the block device is used and the system is in a quiet
    state. fsck(1M) can be run on the raw/character device when
    the filesystem isn't mounted, and this is generally much faster.
    fsck(1M) will automatically reboot the system without sync'ing, if the "mounted" root filesystem was modified, just as you should (since the
    in-core image of the filesystem would be different). There is no
    "re-mount" facility on the UNIX PC, otherwise the root filesystem
    could just be remounted.

    Another suggestion made was to run "fsck -D" to check
    directories for bad blocks. This takes longer, but is considered
    worth it. (fsck -D is similar to the MSDOS CHKDSK facility.)

    ------------------------------

    Subject: 7.8. What does the "-s" option to dismount do?

    It should never be used. It's an historical option (as the
    manual notes), used to un-mount the "Syquest" external drive. This unfortunately causes the first hard disk to RECAL if you don't have
    the second disk upgrade. With the second disk upgrade it improperly
    un-mounts all the filesystems, apparently not handling the /etc/mnttab
    file correctly for all the partitions on the second disk.

    In many people's opinions, it's much safer to use multiple
    /etc/umount commands to unmount multiple partitions. This works for
    all cases, and there is no second guessing on what the command is
    actually doing. If you want to mimic the operation of dismount, you
    can easily issue the "sync" command before the "umount" command. As
    far as clearing the "pulled-flag" as the manual indicates, many have
    never had any problem just using the /etc/umount command (on floppies
    as well as my other partitions and hard disk)

    ------------------------------

    Subject: 7.9. How do I identify what motherboard revision I have?

    [Courtesy of Thad Floryan:]

    The board "schematic" number (in copper) near the left rear
    corner is quite useful when referencing one of the three sets of
    schematics in the Reference Manual. Often the copper number is
    obscured by a white sticker bearing a different number. BOTH sets of
    numbers "almost" uniquely identify your machine. Peel the white
    sticker off and reapply it flanking the copper number.

    The copper board number will (usually) be one of 60-00222-00, 60-00225-00 or 60-00230-00. If yours is 60-00216-00 you have my
    sympathy (the connector to the floppy drive may be pin-for-pin
    reversed from that found on all other motherboards, and you probably
    have the daughterboard above the motherboard). The white paper
    sticker will bear a printed number something like "60-00237".

    The OTHER "number" to write down for future reference is the
    "REV.n" value on the white sticker normally found near the volume
    control sliding pot; this will be something like "REV.C", "REV.F",
    "REV.J", etc.

    The combination of the two sets of reference designators seems
    to uniquely identify all 3B1 systems I've seen. And note that a
    "REV.C" on a "225" board is NOT the same as a "REV.C" on a "230"
    board. And, before you ask, I have NOT been able to determine
    precisely what each "REV.n" represents and I doubt that information
    still exists even at CT (now UNISYS/NCG).

    ------------------------------

    Subject: 7.10. How can the monitor fail?

    [Courtesy of Rob Stampfli:]

    I have witnessed the loss of more than a few Unix-PC monitors
    to a phenomenon where the right side of the screen becomes
    increasingly compressed (nonlinear), at an exponentially increasing
    rate, until the monitor fails completely. Usually, this occurs over a
    period of months, and it usually is observed after the monitor has
    been removed from service, stored, then placed back into service.

    [Rob notes a particular case which was diagnosed by his
    colleague, Harry Maddox, BEFORE the monitor failed completely. He
    writes, "We believe that an actual failed monitor would take out an
    associated transistor and the flyback transformer, unless the monitor
    is fused, presenting a much more difficult problem to fix." The
    particulars:]

    A 4.7 uF 25V non-polarizing electrolytic capacitor (C411) is
    bad. C411 develops a high internal resistance and gets quite hot,
    which further causes it to deteriorate. It may explode -- use
    caution. C411 is located between L402 and T401 inside the monitor
    proper. The value and voltage rating of this capacitor is not
    critical, "ESR" [equivalent series resistance] is however.

    Replace C411 with a mylar capacitor, 4-6 uF @ 25V or more,
    such as AT&T 535GA (4.22 uF @ 100V) or equivalent. Mount on end with insulation on top lead. Dress away from adjacent parts.

    Replace CAP ASAP before further damage is done. Replace fuse
    if blown. Check TR402 for Collector to Base shorts if set was not
    working. Also D403 for short.

    Procedure:

    1. Remove CRT Cover (2 screws in back).
    2. Remove Speaker Assembly (2 screws).
    3. Remove RF Tape from bottom cover (shield). One tape is
    hidden at front of bottom shield.
    4. Remove bottom shield.
    5. A small part (I think a thermal sensor) is found on the
    bottom of the PC board just under C411. It is covered with
    black tape. Remove the tape and bend sensor out of the
    way.
    6. Remove C411 and replace with Mylar capacitor, 4-6 uF, 100V.
    7. Replace sensor and tape.
    8. Reassemble monitor.

    Note: the bottom shield is tricky to remove and replace if you
    don't unmount the monitor from its swivel mount, but it can be done.
    If monitor has failed completely, then check fuse (if present), TR402
    (C-B short), and D403 for a short.

    ------------------------------

    Subject: 8.0. Mysteries

    This section describes some mysteries of the 3b1/unixpc.

    ------------------------------

    Subject: 8.1. What are the LED's left side of the machine for?

    This is from John Milton's HwNotes series #1.

    0 RED: This is the "user LED". It can be turned on and off
    with the syslocal(2) call. It is not used by any
    existing applications.
    1 GREEN: This is the one most people get wrong. This LED
    toggles every time there is a process context
    change, and is cleared on the whole second.
    2 YELLOW: This is the idle LED. When it is on, there are no
    processes in the ready to run state.
    3 RED: Heart beat LED. This is toggled on the whole second.

    This and other interesting information is available in the
    HwNote series 1-15 that are archived on OSU.

    ------------------------------

    Subject: 8.2. What's /etc/update? What does it do?

    /etc/update is an antiquated command which is no longer
    necessary to be used. It is not a shell script, but could easily be
    one. The executable basically takes one argument, the number of
    seconds to sleep, or defaults to 30 (I believe). It then sleeps that
    interval and then issues a sync(2) system call. This is a continuous
    process -- it detaches itself from the current tty with the setpgrp(2)
    call, and closes all file descriptors 0, 1, and 2 (stdin, stdout, and
    stderr). It was to be run by /etc/init, as a boot-time process, and
    was to remain there for the duration of the machine's uptime.

    ------------------------------

    Subject: 8.3. Why did the time display at the top of the screen go away?

    The time at the top of the display is provided by the program /etc/smgr, which combines the functionality of cron, /etc/update, a
    time display, plus maybe a few other mysterious things. Equally
    mysterious is its propensity to occasionally die, leaving a stipple
    pattern in its place.

    As smgr does its cron processing, it logs what it is doing in /usr/adm/cron.log. So that this file does not get too large,
    smgr responds to signal 17 (SIGUSR2) by truncating the log file.
    Unfortunately, smgr will exit if the log file is missing.

    If you want to make sure this does not happen anymore, edit
    /etc/cleanup.wk (the script that runs weekly and sends smgr the
    clean up signal) and add
    touch /usr/adm/cleanup.wk
    before the script sends the signal with "kill -17 $PID"

    Restarting smgr is thankfully unmysterious; become root and
    type "/etc/smgr".

    ------------------------------

    Subject: 8.4. How do I stop that darn double-ESC mode on console windows?

    Some programs that use the TAM (Terminal Access Method)
    library can leave the keyboard (really the shell window) in a strange
    state after leaving. This state is characterized by each press of the
    ESC key injecting two 0x1b characters into the input stream. This
    generally doesn't help anybody -- vi beeps too much, emacs is
    unusable, etc. The fix is to issue the following ioctl from a C program:

    #include <sys/window.h>
    ioctl(0, WIOCSESC, 0); /* to turn off double-esc mode */

    If you really want it back again, do the following:

    ioctl(0, WIOCSESC, 1); /* to turn on double-esc mode */

    ------------------------------

    Subject: 8.5. What do I do when the machine hangs at the boot message?

    Version #.##x
    Real memory = #######
    Available memory = #######
    Main board is ####

    9 times out of 10 the /etc/inittab file is either deleted,
    corrupted, or truncated because of some filesystem damage during a
    system crash.

    The machine will hang there at that Main board prompt forever
    since /etc/init is looking for the inittab file. This is where it is
    handy to have a floppy filesystem disk with saved copy of /etc/inittab
    on it. Boot the system using the "Floppy Boot Disk" (Disk 2 of ##),
    then insert your copy when it asks for the Floppy Filesystem Disk.
    Interrupt the script with <DEL> to get a "#" prompt when the first
    question appears. On your floppy, if you followed the previous
    advice, is /etc/inittab.save, which can be happily copied to the /mnt/etc/inittab file when the hard disk root filesystem (/dev/fp002)
    is mounted from the floppy as /mnt.

    # umount /dev/fp002
    # fsck -s /dev/rfp002
    # mount /dev/fp002 /mnt
    # ls -l /mnt/etc/inittab
    If the file isn't there, or is corrupted:
    # cp /etc/inittab.save /mnt/etc/inittab
    # sync
    # umount /dev/fp002
    # sync
    # sync
    # reboot

    The other one time (out of 10), the /etc/inittab file is okay
    but there is a /etc/utmp.lck file on the system. This happens in very
    rare race conditions involving the pututent(3C) routines. Removing
    this file and rebooting will generally recover the system.

    ------------------------------

    Subject: 8.6. How can the UNIX PC be made more secure?

    The best way to not worry about security is to not allow users
    on your machine that aren't trusted. Especially users that have shell
    access.

    There are several serious problems with the UNIX PC's
    software, specifically the User Agent (UA). The UA (the windowing
    environment, also known as the Office environment) has some serious
    security problems. The best solution, of course, would be to remove
    the entire UA system from your machine. This isn't the easiest
    procedure (since there are lots of programs scattered all around the
    disk that are tied into the UA) and probably not the most desirable
    for some novice users. What's so wrong with it? Well, look in your
    trusty manuals, in section 4. The manual UA(4) states (talking about
    UA configuration files):

    [...] (page 4)
    EXEC and SH have a number of variations, which are used depending
    on the intelligence of the process being invoked.
    [...]
    The variations are specified via option characters as follows:

    -n Run the process without a window
    -w Run the process without waiting
    -d Run the process in a dimensionless window
    -p Run the process with superuser privileges
    [...]

    The "-p" option being the problem. For a little experiment to
    show to a security conscious user (who still likes the UA), start out
    in a non-privileged user account.

    First create a file in your home directory called "Office"
    with the following lines:

    Name=Super User UNIX
    Default = Run
    Run=EXEC -pwd $SHELL

    Then type:

    $ exec /usr/bin/ua

    Select the new object that you just created ("Super User
    UNIX") and then at the "#" prompt type "id" for the effect.

    # id
    uid=0(root) gid=0(root)

    OK, convinced?

    If you really *LOVE* the UA, you can do something about this.
    Protect the programs /usr/lib/ua/uasetx and /usr/lib/ua/uasig so they
    are not executable by "other" and only executable by a "trusted" group.

    -rwsr-x--- 1 root trusted 4268 Jan 1 1970 /usr/lib/ua/uasetx
    -rwsr-x--- 1 root trusted 2068 Jan 1 1970 /usr/lib/ua/uasig

    Another problem involves UA mail-handling. Send yourself some electronic mail. Nothing elaborate is necessary.

    $ mail myself < /dev/null

    Select the [mailbox] icon when it comes up, and then when
    you're in /bin/mail, at the "?" prompt type "! /bin/sh". Poof! Root
    shell.

    # id
    uid=0(root) gid=0(root)
    # pwd
    /etc/lddrv

    This last problem can easily be corrected with Lenny
    Tropiano's "email" program that is archived on OSU as "email.sh.Z".
    That program sets the correct user id, group id, and home directory.

    The other things to look for are covered in lots of books on
    UNIX security: directories with 777 permissions (world writable),
    setuid programs that aren't very security conscious, etc.

    ------------------------------

    Subject: 8.7. How do I access the expert menus in the diagnostics?

    The diagnostic floppy has a mode in it for the more
    experienced system tester. This mode allows the user to skip the
    menus and just specify the test to run. The diagnostic tests can be
    run repeatedly for testing intermittent hardware. The diagnostic
    output can be sent to a parallel printer for review later, and also
    for unattended testing (since the output can scroll off the screen
    rather easily).

    To enter the expert mode, boot the diagnostic disk and type in
    "s4test" at the first menu prompt. The result is the following
    prompt:

    expert>

    From there you can type "?" for a "semi-verbose" command
    syntax, and a list of many of the tests. For more detail on what
    tests and subtests you can do, grab a nice file by Craig Votava (cmv@ihlpf.att.com) called "s4test.info.Z" from the OSU Archives.

    ------------------------------

    Subject: 9.0. Credits

    The following are just a few of the folks who made this list possible.
    Apologies to those who may have been missed.

    James Warner Adams <adams@ucunix.san.uc.edu>
    Brad Bosch <brad@i88.isc.com>
    Brian Botton <botton@iexist.att.com>
    David Brierley <dave@galaxia.network23.com>
    Brant Cheikes <brant@manta.pha.pa.us>
    Alex S. Crain <alex@umbc3.umbc.edu>
    Mark Dapoz <...!cs.utoronto.edu!hybrid!mdapoz>
    Mike "Ford" Ditto <ford@omnicron.com>
    Roger Florkowski <...!cs.utexas.edu!taliesin!roger>
    Thad Floryan <thad@btr.com>
    Darren Friedlien <darren@bacchus.bacchus.com>
    Mark Galassi <rosalia@max.physics.sunysb.edu>
    Robert Granvin <rjg@sialis.com>
    Emmet P. Gray <...!uunet!uiucuxc!fthood!egray>
    Jan Isley <...!gatech!bagend!jan>
    Karl Kleinpaste <karl@cis.ohio-state.edu>
    Gil Kloepfer, Jr <gil@limbic.ssdl.com>
    Jon H. LaBadie <...!princeton!jonlab!jon>
    John McMillan <jcm@pegasus.att.com>
    Perry Miller <pbm@cup.portal.com>
    John Milton <jbm@megalinx.net>
    Scott H. Mueller <scott@zorch.SF-Bay.ORG>
    Boyd Ostroff <ostroff@oswego.oswego.edu>
    Arnold Robbins <arnold@skeeve.ATL.GA.US>
    Gary W. Sanders <gws@n8emr.nitetech.com>
    Rob Stampfli <res@colnet.cmhnet.org>
    Lenny Tropiano <lenny@icus.ICUS.COM>
    Craig Votava <cmv@ihlpf.att.com>
    Norman Yarvin <yarvin-norman@cs.yale.edu>
    Chris Lewis <clewis@ferret.ocunix.on.ca>
    --
    John B Bunch AT&T I don't want the world, I just want your
    9404 N. Church, APT 206 UnixPC half.... -TMBG
    Parma Hgts., OH 44130 IBM PC jbunch@nyx.net
    (440) 887-9310 KB2SIV jbunch@nyx10.nyx.net
    --
    John B Bunch AT&T I don't want the world, I just want your
    9404 N. Church, APT 206 UnixPC half.... -TMBG
    Parma Hgts., OH 44130 IBM PC jbunch@nyx.net
    (440) 887-9310 KB2SIV jbunch@nyx10.nyx.net
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