CD ROM FAQ Interface

Information in this page updated: 24 Sep 95


2. The interface

2.1 SCSI

For anyone who already owns a SCSI-controller(A3000(T), A4000T) there is one choice: buy a SCSI CD-ROM drive. Connecting it is as simply as connecting a harddisk.

And you will get a marvelous piece of hardware that can be conneted to any other known computersystem even if it's not labelled "Int*l *ns*d*".

If tranfer for digital audio data over the interface is a must for you, there is no other choice. Only two brand new IDE-drives offer this feature, but there are no drivers available for the Amiga and those drives.

2.2 AT-Bus

Well, IDE-style CD-ROM drives, often called "AT-Bus"-drives seem to be much cheaper, but you have to pay extra for a special controller or interface/software for the build in controller (for the A600, A1200, A4000 internal IDE-controller).

Why a special controller, they are IDE, aren't they?

IDE or AT-Bus-style drive are not fully IDE as hard disks. There are three differnt connection standards for such drives named after the companies that invented them:

For a PC every drive comes with a tiny special custom controler or it uses the connector on a soundcard (that's why the card come with four (4!) different CD-ROM drive connectors in these days!) None of these drives are able to directly run on an existing Amiga IDE-controller.

Since the Mitsumi is the closed fit to real IDE-interface, there are two known adapters: the bsc tandem (for Mitsumi interface and IDE/ATAPI drives, but it also hosts up to 2 real IDE hard disks) and the CD-ROM-Kit, with adapts the internal Amiga IDE-interface (or the Access!-IDE-adaptor for A2000 by the same manufacturer) to Mitsumi-style connectors. I do not know any kind of hardware to use Sony- or Panasonic- style drives!

But remember that you have to pay extra for the special controller, so a real SCSI or IDE/ATAPI may come cheaper than a combination of AT-Bus drive and controller.

2.3 (E)IDE

In the last month all mayor manufactures have shown new drives labeled EIDE (e.g. the new Mitsumi FX300/FX400). But... these drives finally are true IDE-Drives, and though they run best with EIDE-controllers they will submit to normal IDE-controllers. So you noticed it, their is a little shift in terms: IDE for CD-ROM drives is not IDE for hard disks but some proprietery standrad. EIDE for hard disks is not the same for CD-ROM drives, it's IDE with the new ATAPI definition (which of course is part of EIDE!) for other than hard disk media.

You may smile and try to connect a EIDE-style CD-ROM drive to an existing IDE-controller... it will fail. Any controller for the Amiga is just for hard disks, not for CD-ROMs. This is mainly a software problem, since all interfaces and their drives are not awre of devices other than harddisks on the IDE bus.

So you can connect a IDE/ATAPI drive directly to the A4000, but you'll need a patch of the internal "scsi.device" for that. VOBs SPEEDUP-system will du that for you. So you may not need a hardware-interface but a special kind of driver! Ask the manufacturer of your IDE adaptor for a new software that allows a IDE/ATAPI drive on the bus.

If you have an A600/A1200/A4000 your choice should be the CD-ROM-Kit, so you don't have to sacrifice another valuable Zorro-slot for the controller. For owners of a A2000 with no SCSI-Controller the tandem seems the best choice... if you can't find a working IDE-solution for your controller.

If you connect a CD-ROM to your intrenal IDE bus, you must take care of some things: The CD-ROM drive must be set to act as a SLAVE on the bus and interrupt generation may not be disabled. The harddrive must be set to act as a MASTER. If you have a drive with a combined setting for SINGLE or MASTER operation, leave it that way, if not, rejumper it from SINGLE to MASTER operation.

 Computer        Device                  Vendor                  Type
 ------------------------------------------------------------------------
 A4000
 Access          SpeedCD                 VOB                     commerz.
 Tandem          ad_atapi.device         AlfaData/Oliver Kastl   commerz.
 A600
 A1200
 A4000(T)        atapi.device            Oliver Kastl            PD
 A4000           atapi.device            Georg Campana           PD
VOB offers besides the old kit for the the use of 2 HDs and one Mitsumi-style CD-ROM a new kit caled Multi AT/IDE which allows the connection of 4 HDs and one ATAPI CD-ROM.

Oliver Kastls atapi.device also supports upto 4 devices on the internal IDE with a special adaptor.

2.4 PCMCIA adaptors

For the A600/A1200 with PCMCIA-slots there are several offers for external drives with adaptors that uses this slot. If it's cheap enough for you, go get it. PCMCIA is one of the least used slots anyway, so a good choice for the CD-ROM drive. If you choose a triple or quad-speed drive it will be a real IDE/ATAPI drive on a real IDE controller. This often will allow the connection of some harddrives, too. All these controllers come with special software/drivers so you do not need to fear any incompatability.

 Computer   Adaptor     CD-ROM-adaptor
 ------------------------------------------------------------------------
 A1000/A500 SCSI        SCSI
            AT          ???
 A2000      SCSI        SCSI
            AT          SCSI incl. SCSI controller
                        Tandem
                        CD-ROM-Kit for Access!-controller
 A3000(T)   SCSI        SCSI
 A600/A1200 AT          CD-ROM-Kit, Multi AT/IDE
                        PCMCIA (Overdrive-CD, tandem, Squirrel)
 A4000      AT          CD-ROM-Kit, Multi AT/IDE
                        Tandem
                        Speed-Up System
 A4000T     SCSI        SCSI

 Controller     HDs     CD-ROM drives
 --------------------------------------------------------------------
 SCSI           yes     with SCSI
 Tandem         yes     Mitsumi LU005S, FX001S/D, FX300(FX400
 CD-ROM-Kit     yes     Mitsumi FX-, FQ-Series
 Multi AT/IDE   yes     IDE/ATAPI CD-ROMs
 Squirrel       yes     with SCSI
 Overdrive-CD           Mitsumi(?)

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