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Frequently Asked Questions (FAQS);faqs.002 At this point you should reboot the machine and there should be no unknown device error message on bootup. 3. Formatting the disk Once the system has been rebooted login as root and change the run level to single user mode and remount /usr if need be. At this point you need to cd to /usr/lib/scsi and edit the file tc.index. Add an entry for the new disk in the same manner as the other entries in this file. Make sure that the model number starts in column 9 and is padded out to 16 characters, if you receive an unable to open script file message on formatting the problem is most likely in this entry. At this point you can run the format program from either sysadm or the command line. After the format has finished reboot the system and the disk should be listed as a formatted disk. ------------------------------------------------------------------------------ Subject: 5 How do I prevent data overrun errors when using a high speed modem on an EPORTS card at 19.2K baud or higher? ------------------------------------------------------------------------------ The EPORTS board can easily handle 38.4K baud on an otherwise unloaded system, provided Hardware Flow Control is enabled. The hard part is keeping HFC enabled. Several solutions to this problem exist, but one that seems to work (and I use personally) is to have a daemon set HFC on open lines periodically, and have uugetty enable HFC on all logins. The second part is the trickier part. Elliot Dierksen suggests the following, which I have verified to work: From: ebd@fang.att.com (Elliot B Dierksen) Step 1: copy uugetty to some new name (I used epuugetty). Use some sort of binary editor to change the exec of '/bin/login' to '/bin/ephfc'. Step 2: compile ephfc. Here it is! I have had no problems with this at all, but your mileage may vary. No promises implied or intended. Even with cron entries to set HFC, I still have problems on occasion with dial outs. Inbound calls work great. I hope you all find this useful! ----------------cut here-------------------------------------- /* ephfc.c handle hardware flow control on EPORTS and then exec login This program sets hardware flow control on an EPORTS card in an AT&T 3B2 computer. Patch getty (or uugetty) to exec ephfc instead of login. 04/18/1992 - Elliot Dierksen (e.dierksen@att.com, elliot@alfred.oau.org) */ /* standard header files */ #include <stdio.h> #include <fcntl.h> #include <errno.h> #include <sys/ct_dep.h> #include <termio.h> /* EPORTS header files */ #include <sys/queue.h> /*#include <sys/ep_dep.h>*/ #include <sys/eppc.h> #include <sys/ep_lla.h> #define IN_FD 0 #define OUT_FD 1 main(argc,argv,envp) int argc; char **argv,**envp; { char *login_prog = "/bin/login"; struct etty ettyp; struct termio termiop; /* abort if ioctl read fails. this might happen this is not an EPORT */ if (ioctl(IN_FD,EP_GETA,&ettyp) == -1) { fprintf(stderr,"%s: ioctl(EP_GETA) failed(%d)\n",argv[0],errno); fflush(stderr); exit(6); } /* abort if ioctl read fails. No clue what might have gone wrong! */ if (ioctl(IN_FD,TCGETA,&termiop) == -1) { fprintf(stderr,"%s: ioctl(TCGETA) failed(%d)\n",argv[0],errno); fflush(stderr); exit(7); } /* turn off XON/XOFF */ termiop.c_iflag &= ~(IXON|IXOFF|IXANY); /* set regular ioctl values */ ioctl(OUT_FD,TCSETA,&termiop); /* set EPORTS values */ ioctl(OUT_FD,EP_HFC,0); /* reset arg[0] for login */ argv[0] = login_prog; /* exec login and hope for the best! */ execv(login_prog,argv); } ------------------------------------------------------------------------------ Subject: 6 What does the 'NOTICE: File Table Overflow' error mean? ------------------------------------------------------------------------------ From: v.hoang@att.com It means more files being opened than the limit you've set for the system. Edit /etc/master.d/kernel and bump up the values of NFILE, NINODE & NS5INODE (or something close to that), then cd /boot, mkboot -k KERNEL, touch /etc/system then reboot the system. ------------------------------------------------------------------------------ Subject: 7 How do I set up anonymous ftp? ------------------------------------------------------------------------------ From: rdc30@nmrdc1.nmrdc.nnmc.navy.mil (LCDR Michael E. Dobson) Subject: Anonymous ftp with WIN/TCP 3.0.x YES!! Contrary to the documentation for WIN/TCP 3.0.{0,1}, it is possible to set up anonymous ftp. The Bugs: note in the documentation about it not being fully implemented in this release seems to be just a documentation ommision. I saw the method to use on a US military 3B2 Users Group mailing list. The missing parts are the creation of a dev directory in the root of the ftp account directory with null and tcp devices created with mknod, and the inclusion of the services file in the etc subdir along with group and passwd files. You of course need ls & pwd in bin and a pub tree. Below is the output of ls -lR in my ftp root as well as the passwd in ~ftp/etc/passwd. Try it out and see. total 5 drwxr-xr-x 2 root other 64 Jan 23 11:12 bin drwxr-xr-x 2 root other 64 Jan 23 11:09 dev drwxr-xr-x 2 root other 80 Jan 23 11:13 etc drwxr-xr-x 2 ftp sys 240 Jan 23 11:16 pub drwxr-xr-x 2 root other 64 Aug 28 20:01 shlib /usr3/ftp/bin: total 111 ---x--x--x 1 root other 35678 Jan 23 11:11 ls ---x--x--x 1 root other 19551 Jan 23 11:11 pwd /usr3/ftp/dev: total 0 crw-rw-rw- 1 root sys 63, 43 Aug 28 19:57 circ crw-rw-rw- 1 root sys 49, 2 Jan 23 11:09 null crw-rw-rw- 1 root sys 63, 38 Jan 23 11:09 tcp crw-rw-rw- 1 root sys 63, 36 Aug 28 19:56 udp /usr3/ftp/etc: total 4 -r--r--r-- 1 root other 336 Jan 23 11:12 group -r--r--r-- 1 root other 56 Jan 23 11:13 passwd -r--r--r-- 1 root other 884 Jan 23 11:12 services /usr3/ftp/pub: total 0 /usr2/ftp/shlib: total 211 -r-xr-xr-x 1 root other 66626 Aug 28 20:01 libc_s -r-xr-xr-x 1 root other 39859 Aug 28 20:01 libnsl_s Contents of ~/ftp/etc/passwd: ftp:x:13:1:Anonymous FTP Account:/usr3/ftp:/usr/bin/ftp -- Mike Dobson, Sys Admin for | Internet: rdc30@nmrdc1.nmrdc.nnmc.navy.mil nmrdc1.nmrdc.nnmc.navy.mil | UUCP: ...uunet!mimsy!nmrdc1!rdc30 AT&T 3B2/600G Sys V R 3.2.2 | BITNET: dobson@usuhsb or nrd0mxd@vmnmdsc WIN/TCP for 3B2 | MCI-Mail: 377-2719 or 0003772719@mcimail.com A special note from Steven M. Kilby <skilby@ucqais.cba.uc.edu> Anonymous FTP for the 400: Setting up an anonymous FTP login for the 3B2/400 differs slightly from the instructions in the FAQ. The FAQ instructions will work on 600's or 1000's. The only changes are in the directory setup. [As other people found the original anonymous FTP setup did not work at all without Steven M. Kilby's changes, I modified the directory structure above to reflect Steve's changes. -greg] Also: From: Kevin Darcy <kevin@cfctech.cfc.com> Also, you should probably make people aware that the exact minor numbers for all clone devices will vary from system to system, and to only use the ones displayed as a guide. For instance, my dev entries for circ, tcp & udp are crw-rw-rw- 1 root other 63, 66 Sep 10 1991 /dev/circ crw-rw-rw- 1 root other 63, 56 Sep 10 1991 /dev/tcp crw-rw-rw- 1 root other 63, 58 Sep 10 1991 /dev/udp which is somewhat different than what's shown above (cfctech's major numbers are higher than most folks', because we have run StarLAN, Datakit & WIN/TCP all simultaneously on the machine, in addition to everything on the release tape, and, at one point, even loaded X Windows on the box (!)). ------------------------------------------------------------------------------ Subject: 8 Is there a reposity of ftp-able 3B2 programs? ------------------------------------------------------------------------------ The following are some 3B2 ftp sites that I know of and what they contain: ames.arc.nasa.gov (128.102.18.3) Kyoto-Lisp, Pascal, Sendmail, citadel-bbs ds3.bradley.edu (136.176.5.79) X11R4, old gcc erratic.bradley.edu (136.176.5.253) X11R4, old gcc stasi.bradley.edu (136.176.5.121) xarchie, lpr/lpd And then there's... From: Jeffrey A. Thompson <jeffrey@rigel.econ.uga.edu> Here is a list of software I have compiled on my 3b2 (roscoe.msit.uga.edu) available via anonymous ftp. I have all the source too. 287172 Nov 19 13:37 bash* GNU's Bourne Again Shell 35137 Apr 5 1990 compress* 5959 Aug 22 20:55 culimit* Program to change the ulimit of a shell to 10 megabytes instead of 1 megabyte. 48615 Jan 25 11:10 gab* My own little talk program for up to 19 people ; uses shared memory and semaphores 174992 Aug 23 1990 kermit* The standard kermit. 60393 May 19 1990 rb* X/Y/Z modem 60393 May 19 1990 rx* 60393 May 19 1990 rz* 59254 May 19 1990 sb* 32546 Nov 6 08:17 ship* Zip's ship 59254 May 19 1990 sx* 59254 May 19 1990 sz* 35137 Apr 5 1990 uncompress* 61743 Nov 6 08:17 unzip* Unzip ; I love zip. It works on everything. and better compression than compress (average 10 to 30 percent better compression) 38784 Jun 22 1991 uudecode* 23781 Jun 22 1991 uuencode* 20844 Sep 7 17:51 uvapc* A standard pascal compiler 35137 Apr 5 1990 zcat* 75420 Nov 6 08:15 zip* Can produce pkzip compatible zips (-k opt) 35188 Nov 6 08:15 zipnote* 36904 Nov 6 08:15 zipsplit* Splits up a zip file into smaller zip files Great for copying stuff onto a floppy disk. --jat And then there's... From: Steven M. Kilby <kilby@ucqais.cba.uc.edu> Starting October 1 ucqais.cba.uc.edu will offer an anonymous login service specifically for 3B2 users. The anonymous login will contain software packages that have been ported to the 3B2, such as gcc, iscreen, lpr, X11, and many more! Most of the offerings will be binary, although I will include as many sources as I can. If there are any packages you would like to see available there, let me know! ------------------------------------------------------------------------------ Subject: 9 How do I run Unix from floppy (for example, to repair a damage hard drive file system)? ------------------------------------------------------------------------------ Running a Standalone Shell on a 3B2 Stephen J. Friedl [Edited by Gregory Gulik] April 25, 1988 NB: the procedures described here require substantial knowledge of UNIX and entail a significant risk of causing loss of data. The obvious disclaimers apply here, so use at your own risk. Please be careful. Introduction This document is an introduction to operating your 3B from a standalone /unix. Even with inoperable hard drives, it is possible to insert the boot floppy (Essential Utilities Disk 1), say some magic words, and receive a # prompt. At this point you can do major surgery on the failing machine, often recovering a drive previously thought to be lost. Our style is informal and we'll use lots of examples to illustrate the points at hand. We have been using standalone shells for quite some time and have learned a great deal; we hope to pass this information on to you. Please read this document carefully before trying the methods described here, and if possible have a wizard around when giving it a go. This can be dangerous business: as has been said before, it is a time where experience and informed courage count for much. Conventions Throughout this document, sample usage sessions will be shown indented, with user input in bold. To make it easier to distinguish between a multiuser UNIX shell and a standalone one, we will show multiuser UNIX's root prompt as ## and the standalone prompt as #. >>> Back up your boot disks b-> This cannot be emphasized enough. Your boot floppies are the key to your machine, and without them the machine is down. Why do you want a standalone /unix? The most compelling reason for a standalone shell is when the primary drive has gone down and must be recovered. While working from a standalone /unix is slow and tedious, it can often save an entire hard disk with minimal data loss. We have also used this standalone shell to repair a corrupt /etc/inittab, to fix /etc/passwd, to restore a /bin/login that had been removed, and to install new bootstraps on the hard drive. With a standalone boot disk in hand, a host of possibilities presents itself. What is on your boot disk? Before booting this floppy, take some time to explore its contents, as the disk has a filesystem on it that can be mounted and perused. To do this, insert a COPY of the Essential Utilities Floppy 1 (from now on, "the boot floppy") into the drive with a write-protect tab. Now, ## mount /dev/dsk/c0d0s5 /install -r Because boot floppies vary from release to release, it would be most helpful to simply get a listing of the contents of your particular boot floppy. Once finished, the floppy must be unmounted: ## cd / ## umount /dev/dsk/c0d0s5 "Open Sesame" To give standalone a try, first shut the machine down to firmware mode. Assuming the machine is now in firmware mode, put a copy of the boot disk into the drive. Note that some versions of the operating system (Sys V Release 2, at least) require that the boot floppy be write-enabled (i.e., no write-protect tab); it is this requirement that mandates multiple backups of the boot floppy. UNIX will be updating the disk while it runs -- the superblock, access times, etc. -- and if the machine crashes at the wrong time it simply will not boot again without an fsck. Be careful. Type in your firmware password and boot /unix from the floppy drive (Option 0, named `FD5') instead of the hard drive (Option 1, named `HD30' or `HD72'). It can take several minutes for UNIX to boot, but when it does, the familiar menu will be displayed: 1) Full Restore 2) Partial Restore 3) Dual-Disk Upgrade 4) Release Upgrade Selection? [1, 2, 3, 4, quit, help] At this point, type the phrase magic mode The system recognizes this special option and responds: Poof! Selection? [1, 2, 3, 4, quit, help, shell, copy] Notice the new options? Now type shell, then RETURN, and you will be greeted with the familiar # prompt. You are now running a standalone shell on the floppy. A few reminders here: a floppy filesystem is not able to hold much data, and many common utilities are unavailable. When dealing with the standalone shell, one must learn alternatives to these utilities. For example, echo * can replace ls(1), and cat > file can serve as a poor replacement to ed(1). One must become remarkably resourceful when working in an environment as restricted as this. We will see later how we can enhance this confined environment with additional tools. Standalone devices The floppy's /dev directory contains a host of entries, some of them referring to partitions on the hard drive. While a particular partition may have several names, we generally use the following devices to refer to the hard disk: Partition What it is (on the hard disk) ----------- ----------------------------- /dev/idsk00 / filesystem /dev/idsk01 swap area /dev/idsk02 /usr filesystem /dev/idsk06 the entire disk /dev/idsk07 boot partition /dev/idsk08 optional filesystem (/u or /usr2) Mounting the hard drive To gain access to the primary hard drive, partitions of interest are mounted onto directories on the floppy. The device names are selected from the table in the previous section. Before mounting a partition, we recommend running the filesystem check fsck(1m) first. The mount command will fail if the the superblock is not in order -- this is often the case after a crash. In addition, it gives a convenient verification of the device status and the the filesystem's name and volume. # /etc/fsck /dev/idsk00 While some errors are to be expected while checking the root partition, a total failure is a very serious error. Our experience defines "total failure" as an indication by fsck that it cannot find any possible traces of a filesystem. In particular, "CAN NOT READ: BLK 1" is one of the more ominous messages we have seen. Once fsck grants the filesystem a clean bill of health, it is ready to be mounted. Rather than take up space for a handful of common commands, AT&T has rolled several of them into one: fsys. It is undocumented and appears to only be used on the boot floppy. Some versions of the boot disk do contain the mount and umount programs and those can be used instead of fsys. Fsys takes a handful of options, not all of which are interesting to us in standalone mode. Used in the install scripts for a handful of filesystem-related duties, we will use it simply as a replacement for mount(1m) and umount(1m). To mount the hard disk's root filesystem onto the floppy's /install directory, do: # fsys -m /install /dev/idsk00 Fsys will complain on an error, and this brings us to a serious bug in this program: if either the mount directory or the partition's device name are invalid for any reason, the error message will always point to the partition device name. This can be, to put it lightly, "misleading". With the hard drive's root filesystem mounted on /install, it is now fully part of the standard directory tree. While the floppy has no editor or many of the helpful tools, the root partition does, and these can be exploited. When beginning an extended standalone session on the primary drive, we have found it helpful to extend the shell's search path: # PATH=/install/bin:/install/etc:$PATH ; export PATH Now the familiar ls, ed, (but not vi) and many other commands are available. Since they will be loaded from the hard drive, execution is much faster. As an example, assume that the root password has been forgotten and the machine is basically closed. The solution suggested by AT&T's documentation (in the System Administration Utilities Guide) is to do a partial restore. The difficulty with this approach is that many important system files -- /etc/passwd, /etc/inittab, /etc/gettydefs, and others -- are overwritten in the process. Even with a full backup, this can be an unpleasant undertaking. An alternate approach will use the standalone shell. The general strategy is to mount the hard drive, edit the password file, and boot multiuser UNIX. The full procedure is: (boot standalone /unix) # fsck /dev/idsk00 # fsys -m /install /dev/idsk00 # /install/bin/ed /install/etc/passwd (edit the file in the standard way) w q # fsys -u /dev/idsk00 At this point, the root drive is now unmounted and the system may be rebooted. Normally you can just type exit at the shell prompt and you will be returned to the monitor and asked what program to boot. If that doesn't work on your version, try: # sync # sync # /etc/uadmin 2 2 Uadmin(1m) is documented in the manual (you must also refer to the uadmin(2) manual page) -- the above does a normal return to the monitor (i.e., firmware). WARNING: uadmin(1m) is available from full UNIX as well but is very dangerous. Use it with extreme caution and only if you really know what uadmin does. Making a standalone boot disk ================== WARNING ================== Only do this on backup copies of the disks, NEVER to the main Essential Utilities Disk. ================== WARNING ================== The Essential Utilities Disk 1 contains many files needed by the automatic restore/upgrade procedures, but for standalone work, many are not needed. After working with these disk for some time, we were able to narrow down what is helpful to have on the disk and what is not. The following procedure (run from multiuser mode, signified by the ## prompt) will convert an Essential Utilities disk to a standalone boot disk. (from hard disk UNIX) ## fsck /dev/dsk/c0d0s5 ## mount /dev/dsk/c0d0s5 /install ## cd /install/inst/bin ## mv fsys pdinfo swap ttyset ../../bin ## cd /install ## /bin/rm -rf inst ## cp /bin/ed /install/bin ## cp /etc/fsdb /install/etc ## cat > /install/inittab is:s:initdefault: sh:s:respawn:/bin/sh < /dev/console > /dev/console 2>&1 ^D ## cd / ## umount /dev/dsk/c0d0s5 While there may be other files on this floppy that are not needed, we have operated on the principle of least customization. It has been our experience that keeping the procedure simple allows it to be done on-the-fly (say, at a customer site) and minimizes the exploration required when a new operating system disk is released. In addition, it is not wise to pack the disk too tightly. The editor requires adequate space under /tmp, so an almost-full disk precludes editing all but the smallest files; this applies whether the file being edited resides on the hard drive or the floppy. Once this is done, the new disk will come up in standalone mode without the need for magic mode. In addition ed(1) and fsdb(1m) are available. The other tools mentioned (pdinfo, swap, ttyset) are helpful but not required by the basic procedures. It has been our experience that any version (SVR2, SVR3) of boot disk can be used with any version of hard disk UNIX without difficulty for doing simple operations such a performing filesystem checks or editing /etc/passwd. For more complex operations, such as repartitioning the hard drive or restoring the bootstraps, higher version compatibility is required. Security Considerations It should be apparent that knowledge of these standalone methods is tremendously powerful. In addition to being able to rescue a foundering machine, an unrestricted path to root has been provided as well. While all the standard rules about physical security of the computer apply here, an additional step may be taken to thwart a would-be interloper. The responsible system administrator of a machine in a hostile environment will generally change the computer's firmware password. This magic word is required before the monitor on the 3B2 motherboard will boot from a floppy, and lack of this password prevents a malicious user from simply pulling the power plug to enter firmware mode. In addition to changing the firmware password, the floppy key floppy should itself be secured. When the computer is restarted with this disk in the drive, it will clear the non-volatile RAM (NVRAM) and restore the default parameters. Because the firmware password is included in these "default parameters", this disk should be kept out of non-trusted hands. Conclusion We solicit bug reports, comments, and suggestions on this document. Please direct them to: Stephen J. Friedl Software Consultant 1891 Running Branch Way Tustin, CA 92680 +1 714 544-6561 voice +1 714 838-0099 fax Internet: friedl@mtndew.Tustin.CA.US Usenet: {backbones}!uunet!mtndew!friedl ------------------------------------------------------------------------------ Subject: 10 What is/was the 3B Journal? ------------------------------------------------------------------------------ The _3B Journal_ was put out sporadically by Owens-Laing Publications for several years in the late 1980s, and I used to be the technical editor. The magazine dealt with the 3B1 and 3B2 platforms, and the content varied from very markety-oriented to quite technical (the latter usually written by me). The publisher never seemed to get a handle on the business end of running a magazine, and I've heard nothing past the fourth quarter, 1989 issue. The current phones are disconnected, and I have NO information on subscriptions or anything like that. -- Stephen Friedl friedl@mtndew.Tustin.CA.US 3/12/1992 ------------------------------------------------------------------------------ Subject: 11 What are the various models of 3B2s and their differences? ------------------------------------------------------------------------------ [I'm putting this together mostly from memory and from discussions with other people. Please feel free to make corrections.] Some corrections/aditions provided by Andrew D. Hay <adh@petrel.att.com>, Paul S. Sawyer <paul@unhtel.unh.edu>, Mike Crom <crom@vogon.att.com>, David Beneman <..!uunet!tacoma!dcb>, Paul Rak <pjr@emo.com> The 3B2 family of consists of the following models: 3B2/300 Processor: WE32000, 8 MHz almost 1 MIPS Memory: Supports a maximum of 4 MB of RAM using two half height 2 MB memory cards. Slots: 4 standard slots. Features: MFM disk controller on motherboard 1 internal full-height drive bay 1 720 K floppy drive 3B2/310 Processor: WE32100, 10MHz (supports optional MAU) 1.1 MIPS Memory: Supports a maximum of 4 MB of RAM using two half height 2 MB memory cards. Slots: 4 standard slots. Features: MFM disk controller on motherboard 1 internal full-height drive bay 1 720 K floppy drive 3B2/400 Processor: WE32100, 10MHz (supports optional MAU) 1.1 MIPS Memory: Supports a maximum of 4 MB of RAM using either two half height or full height 2 MB memory cards. Slots: 12 standard slots. Features: MFM disk controller on motherboard 2 internal full-height drive bays 1 720 K floppy drive 1 23 MB cartridge tape drive 3B2/500 Processor: WE32100, 18MHz 2.1 MIPS 2.6 MIPS w/VCache 4.0 MIPS w/MPE Memory: 2 - 4MB cards max Slots: 7 I/O + 4 system (MEM0, MEM1, Vcache, BUB0) There is also BUB1, but it is listed as unusable without the 22MHz upgrade. Features: SCSI disks Up to 1 additional MPE 3B2/522 Processor: WE32200, 22MHz 5.0 MIPS Memory: 2 - 16MB cards max Slots: 7 I/O + 4 system (MEM0, MEM1, Vcache, BUB0, BUB1) Features: SCSI disks Field upgraded 3B2/500 to same processor as 3B2/700 Up to 1 additional MPE 3B2/600 (aka 3B2/1000-60) Processor: WE32100, 18MHz 2.6 MIPS 4.0 MIPS w/MPE Memory: 4 - 4MB cards max Slots: 12 I/O + 12 system Features: SCSI disks 120MB SCSI tape Up to 3 additional MPEs 3B2/700, 3B2/622 (aka 3B2/1000-70) Processor: WE32200, 22MHz 4KB PCache 5.0 MIPS 7.5 MIPS w/1 MPE 8.5 MIPS w/2 MPEs 9.0 MIPS w/3 MPEs Memory: 4 - 16MB cards max Slots: 12 I/O + 12 system Features: SCSI disks 120MB SCSI tape Up to 3 MPEs The 3B2/622 is a field upgrade for the 3B2/600 3B2/1000, 3B2/600G (aka 3B2/1000-80) Processor: WE32200, 24MHz 9 MIPS 16 MIPS w/3 MPEs Memory: 4 - 16MB cards max Slots: 12 I/O + 12 system Features: SCSI disks Up to 3 MPEs 3B2/1050 R3 Processor: MIPS R3000A, 33MHz Memory: 16MB - 32MB Slots: N/A Features: N/A 3B2/1100 R3 Processor: MIPS R3000A, 33MHz Memory: 32MB - 64MB Slots: N/A Fetures: N/A 3B15 Processor: WE32100 (standard MAU) (?) 2 MIPS (?) Memory: 16 MB (?) Slots: Features: Standard 9-Track tape drive Uses 8 inch SCSI drives NOTE: Not all 3B15s have SCSI. Some models were converted from 3B5s and have 8 inch FSD drives (maximum 8, 160 MB or 340 MB). Then there are the Lark II drives. The non-SCSI tape bus can take 1-4 drives. The 3B5 becomes a 3B15 by a change of 2 (??) boards, and most importantly, a new name sticker!