ARCO AC-1070
There are two variants of this- the AC-1070 and the AC-1070EXT (External)
@6263.adf (Lastest version, 07/02/95) Sorry, but my ISP is the limiting factor here. Rename A6263.txt to @6263.adf.


AC-1075 (?)

This version seems to be an advanced version of the 1070. Note the much reduced chip count.

J1, J4 Two pin headers
J2 Drive power connector
J3 A three pin header that has pins 2 and 3 shunted
P1 IDE connector
U1 ?
U2 ?

IDE in an IML Machine?
  Well, sort of. The IDE controller can only be installed in a non-IML machine, such as the 8580, or a 90/95/85 with Flash BIOS. If you have a Type 1 upgrade DX2-66 complex OR a Type 4 complex, OR a 9585 then you can use this controller and IDE drives. I installed an AC-1070 and hooked up a WD-AC2420 drive in my 9590-OPT....

System Partition on IDE?
   Yes and no. Yes it will install a system partition, BUT it will be a 3MB primary partition. You can install an extended partition, but you still cannot access the system partition the drive laid down (shades of the IBM Fast SCSI-2). Of course, the AC1070 does not use the Int4b interface required by IML systems...

Start Up Sequence
   Make sure you select A: then Hard Drive 0 in startup sequence if you want to boot from the IDE drive. If you have a SCSI controller, you can have a SCSI drive selected as the boot device.

AC-1070 with IBM SCSI Adapters under W95
  Although the startup sequence functions just fine selecting either the IDE drive or the SCSI drive for a start up device, W95 bombs when you try to look at hardware performance. There is no provision in the ARCO adf to change the AC-1070's IRQ from 14. And everyone knows that the IBM SCSI adapters only have IRQ 14 support. Though the two IO ranges are seperate (ARCO in the 200s, IBM in the 300s) W95 can't handle the shared IRQs.

W95 and the AC-1070
  From a snippet- (Looks as if Win95 does not recognize the Arco as valid IDE controller ... control panel does not even show the HD). 

More to come. I must get my 9590 back up to install W95 on an IDE drive....

BIOS Capabilities
Version E (BIOS EPROM ver 3.03) supports 2Gb hard disk on PS/2 70; but version C (BIOS EPROM ver. 3.00) only supports 540 meg (525 Mb) hard disk in the same system. 

Which version of the BIOS supports CD Roms?

From Peter
Hi Tim !
 >The .ADF for the Arco makes NO reference to the IRQ used (if any). Now this could mean that it's hard-wired to IRQ14 (as is the onboard ESDI), or that it is I/O polled.
   It seems to be used in PIO mode. If it were using any IRQ it should have the INT mentioned under "fixedressources" as have the IBM MCA SCSI controllers like in the below example:
        int 0eh
   The ARCO also uses 16 I/O adresses on 2510h to 251Fh (alternatively: 2520h - 252Fh), which is pretty unfamiliar. Usually the IDE adapters uses 8 I/O ports in the 1F0h - 1F7h (170h - 177h secondary) as data-port and 3F6h (376h secondary) as control-/ status port. And IRQ 0Eh (0Fh) as interrupt.
    So the Arco is anything but not a standard IDE-controller anyway. I  think it is best used under DOS/Win3.x or (probably) OS/2 ... not recommended for Win95 / 98 / NT - as usual.
   The ROM-BIOS -by the way- can be set to disabled in the Setup. Will continue the quest on Thursday ...

Max Drive Size
   The ARCO may not see the 2.5(doubtful) It does have an EIDE limit of  2.1GB accordingly and also supports internal EIDE CD-Roms(for 5.25 inch bay units).  But the it has its own Drive table settings on the card.  Most likely when you preformatted the drive on a different computer the Cyls/Hds/S-T are different than what the BIOS on the card is going to see

  The AC-1070 controller's adapter BIOS supports IDE drives up to 2 Gb.  If a drive was partitioned and formatted to a higher capacity, the controller will not permit the drive to operate under that partitioning scheme. 

  My question- will it allow multiple 2.1 GB partitions?

  The @6263.adf, dated 07/02/95 has a section for CD Rom support.

   MCIDE.EXE shows you the configuration of any hard drive attached to an Arco MCA hard drive adapter.  The program displays the drive information provided by the hard disk manufacturer, so it may not always be accurate.  MCIDE.EXE will also display the Arco adapter information. MCIDE.EXE is available on the Arco BBS (305-925-2791). ( Ed. Is it?)

ATAPI CDROM Installation
  Oops, my only ATAPI CD-Rom nuked itself (plastic gear snapped off). When I find out more, I'll tell.

ADF Sections

Adapter Memory Location  DC00, D800, D400, D000, CC00, C800, or ROM DISABLE.

IO Address 2510-251F or 2520-252F 

Slave Drive ATA Device,  ATAPI Device or Not Installed. Necessary to support ATAPI device (CDROM) that is connected to the system as slave drive

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