My Love Affair with the Amiga...

My Current configurations:

Amiga 500 Rev. 5 ``B-52 Rock Lobster'' with:
ECS Agnus, (1MB ChipRAM and PAL video hacks applied), ECS Denise,
Phase 5 BliZZard Turbo Memory Board (14MHz) w/8MB FastRAM, SupraRAM 500 in trap door, SupraDrive 500XP on expansion connector,
Quantum LP240S (233MB), Plus Development (Quantum) 210S (199MB) SCSI hard disks, Maxtor XT1140 (223MB) and Priam AT-130/D2 (223MB) MFM hard disks (via Adaptec ACB4070 SCSI RLL hard disk controller),
Amiga OS 3.1 (KS 40.63, Exec 40.1, WB 40.42)

Commodore CDTV, which I use as a network CDROM drive for the A500 via ParNet. It's also one killer audio-CD player!
The system includes the genuine CDTV Black Keyboard and Mouse, and the CD1300 genlock.
The "SCSI-TV" SCSI host interface from AmiTriX Development is installed in the expansion bay with an IBM WDS2120 (119MB) 2.5-inch drive (previously used in a Mac(!) PowerBook and which I picked up cheap) mounted on the board. Also available, the Quantum LP52S (49MB) which I previously used on my A500 (above).

Amiga 500 Rev. 6a ``B-52 Rock Lobster'' with:
ECS Agnus, (1MB ChipRAM and PAL video hacks applied), OCS Denise,
Phase 5 BliZZard Turbo Memory Board (14MHz) w/3MB FastRAM, A501 clone in trap door, Spartan SCSI Interface (with updated drivers/utilities) on expansion connector,
Seagate ST-296N (80MB), ST-138N (31MB), and Rodime RO5125ST (98MB) SCSI hard disks. Other random SCSI devices as desired/necessary.

In the process of building (from scratch) and using the Spartan SCSI Interface, I uncovered a problem with the hardware design and a bug/shortcoming with the device driver. I've patched the driver to eliminate its problems and I'm in the process of testing a modification of the hardware design. Specifically, the interface is not reliable on an accelerated machine when using an Adaptec (or similar) SCSI MFM/RLL/ESDI/etc. hard disk controller. The device driver could not handle a disk larger than 512MB due a coding error. It also had trouble with disks larger than 1GB due to the sector-address limitations of the SCSI class ``0'' six-byte read/write commands.

Patched device drivers for the Spartan SCSI Interface are now available. See my Amiga Hacks section for a brief description. (My initial attempt at modifying the hardware was not successful, but I plan to return to that project in the near future.)

What do I do with all of that?

Lately, I've been experimenting with video titling with the CDTV, the CD1300 genlock and JACOsub v2.2.

My Amiga 500s are 'net-connected with AmiTCP v4.0demo, PPP.device v1.45 (registered! :-), AMosaic v2.0(pre-release 3), IBrowse v1.02demo, ALynx v1.31, and GUI-FTP v3.x. I also have AmigaELM and Amiga "tin" v1.3 up and working very well. Previously, I used MLink v1.34 and AMosaic v1.4beta. I started out some time ago with DNet and AMosaic v1.2. Fantastic!

For non-TCP/IP telecommunicating, I use Olaf Barthel's excellent ``term'' v3.4. For preparing all my necessary printed documents and correspondence, I use Georg Hessman's fabulous PasTeX implementation of the TeX typesetting language.

I also enjoy collecting electronic music and image files. I use an excellent program called ``Multiplayer'' v1.32 and ``HippoPlayer'' v2.30 to play ``.MOD'' music modules (in the background) while working on other tasks. I registered Ed Hanway's excellent ``HamLabPlus'' image-processing software and have had good results converting nearly any image file into a suitable IFF format for rapid, brilliant display on the Amiga.

True, like my other computers, the Amiga is a source of fascination and study. It has a ``hackable'' feel to it that hasn't been seen in any computer since the old Apple ]['s came out.

Ever since I saw my first Amiga (a former roommate of mine had a similar stock Amiga 500), I knew I wanted one. I've not regretted that decision. To me, the Amiga represents all the ``Good Things'' in computer hardware and operating system design. I still marvel at how the Amiga can do things with 512K of EPROM, 512K of RAM, 880K of disk space and a 7.15909 MHz 68000 that takes other systems 8MB of RAM, 40MB of hard disk space and a 33MHz 80386+ to do!

Amiga Hacks!

Late-model Amiga 2000 2MB ChipRAM hack

Originally published in the February 1993 Amazing Computing/Amiga, this hardware modification allows installation of the 2MB Agnus directly in the old Agnus socket of a late-model Amiga 2000, without using any piggy-back adapters or add-on cards.

This is the text version by Kenton Groombridge that provides more "how to" details. The XCLK MUX circuit instructions contained an error, which I corrected. I also provide a much-simplified version of this circuit, shown here.

This hack requires no small measure of skill with electronics repair. If you are not comfortable with cutting traces on your belovéd Ami, you should not perform this hack yourself!

Amiga 2000 to CDTV to Amiga 500 Keyboard Adapter

After looking at many similar hardware projects/hacks on AmiNet, I was disappointed and disgusted that they were inconsistent with each other (and often with themselves!). I wanted to prepare a first-rate schematic that shows the wiring with explicit references to pin number, signal name, and orientation/sex of the referenced connector.

Also, I wanted to maintain the ``Control-LeftAmiga-RightAmiga'' keyboard reset ability. Other hacks simply used a separate pushbutton switch to allow the A500 to be reset. I wanted to maintain full functionality while using the Amiga 2000 and/or CDTV keyboards.

With direct help from Tom Weeks (aka Tom D Tek, aka Mr. Bandwidth), a friend and fellow Amiga user; indirect help from Dr. Peter Kittel, Escom/AT; and e-mail help from Dave Haynie, I constructed an adapter as shown in the schematic. The keyboard reset circuit is identical to that of the Amiga 2000.

Amiga 500 owners, note: Depending on how old your machine/manual is, the schematic drawing in the back of the manual may have the labels for ``_KBDATA'' and ``_KBCLOCK'' reversed! The schematic of the adapter shows the correct labelling, which is consistent with the A2000.

There had been some controversy as to the correct pin-numbering sequence of the 5-pin mini-DIN connector used on the CDTV keyboard. The numbering shown in the schematic is the correct numbering for a 5-pin mini-DIN. Be sure to note the sex and orientation of the connector.

If you plan to attach a CDTV keyboard to your A500 via this adapter (or build a cable to adapt the CDTV keyboard to your A2000), then you must buy a genuine 5-pin mini-DIN connector. DO NOT buy a 6-pin mini-DIN just because the pin-positions match. The keyway of the 6-pin mini-DIN is offset towards the top of the connector, whereas the keyway of the 5-pin mini-DIN is located in the center. The mini-DIN-5M can only be plugged into a mini-DIN-6F if you're willing to break the key out of the mini-DIN-5M.

Spartan SCSI Interface (revised design by John D. Baker)

The revised device drivers come in two patch flavors for both Adaptec/generic and embedded SCSI drives. The first just fixes the 512MB problem and allows full access to drives up to 1GB (the limit for SCSI class-0 read/write commands). The second uses the SCSI class-1 ten-byte read/write commands to allow full access to drives up to 1TB (terabyte) or the limit of the AmigaDOS file system, whichever is smaller (2GB, if I recall correctly).

These folks also help to make it possible:

Index of ftp.luth.se/pub/ (Swedish Aminet Site)
Aminet at ftp.wustl.edu
Michael J. Witbrock
Scientific Amigan

Copyright © 1995 John D. Baker, jdbaker@NoSpAm!blkbox.com
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