FreeBee - AT&T 3B1 emulator
FreeBee is an emulator for the AT&T 3B1. It's a work-in-progress, but currently works well enough to boot the operating system.
Phil Pemberton -- email@example.com
Things which are emulated...
- Revision P5.1 motherboard with 68010 processor, WD2010 hard drive controller and P5.1 upgrade.
- 720x348 pixel monochrome bitmapped graphics.
- 4MB RAM (2MB on the motherboard, 2MB on expansion cards).
- This is the maximum allowed by the memory mapper.
- Keyboard and mouse.
- WD2010 MFM Winchester hard disk controller.
- Maximum 1400 cylinders (limited by the UNIX OS, see the UNIX PC FAQ, section 5.6).
- Heads fixed at 8.
- Sectors per track fixed at 16.
- Fixed 512 bytes per sector.
- WD2797 floppy disk controller.
- Double-sided, 512 bytes per sector, 10 sectors per track, any number of tracks.
- Realtime clock.
- Reading the RTC reads the date and time from the host.
- Year is fixed at 1987 due to Y2K issues in the UNIX PC Kernel.
Things which aren't emulated fully (or at all)
- Serial ports (or Combo Card)
- Printer port
- You will get errors that '/dev/ph0 cannot be opened' and that there was a problem with the modem. Ignore these.
- Second hard drive (WD2010 driver stores the drive-select state, but doesn't use it)
- Install the
- Clone a copy of Freebee (remember to check out the submodules too)
- Build Freebee (run 'make')
- Download the 3B1 ROMs from Bitsavers: link
- Download the 3B1 Foundation disk set from Bitsavers: here
- These will need to be converted from Imagedisk to binary format
- The disk images on unixpc.org don't work: the boot track is missing.
- Unzip the ROMs ZIP file and put the ROMs in a directory called
- Create a hard drive image file:
dd if=/dev/zero of=hd.img bs=512 count=$(expr 16 \* 8 \* 1024)
- This creates a "Miniscribe 64MB" (CHS 1024:8:16, 512 bytes per sector).
- Note that you need the Enhanced Diagnostics disk to format 16-head hard drives.
- Install the operating system
- Follow the instructions in the 3B1 Software Installation Guide to install UNIX.
- To change disks:
- Press F11 to release the disk image.
- Copy the next disk image as "discim" in the Freebee directory.
- Press F11 to load the disk image.
- After installation has finished (when the login prompt appears):
- Log in as
cp rc rc.old
sed 's/.phinit .modeminit//' rc.old > rc
- The above commands disable the phone and modem initialisation, which crash due to un-emulated hardware.
- Log in as
- F10 -- Grab/Release mouse cursor
- F11 -- Load/unload floppy disk
- Alt-F12 -- exit
- AT&T 3B1 Information -- the "Taronga archive".
- Includes the STORE, comp.sources.3b1, XINU and a very easy to read HTML version of the 3B1 FAQ.
- Also includes (under "Kernel Related") tools to build an Enhanced Diagnostics disk which allows formatting hard drives with more than 8 heads or 1024 cylinders.
- Bitsavers: documentation and firmware (ROMs), software