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Began: Sat, 23 Jun 2012 14:02:16
Subject: Emulation of the real SCSI hard disk and floppy disk drives in a Macintosh Plus
Mini vMac currently does not emulate a Macintosh Plus with real SCSI floppy disk and hard disk drives, and instead patches the ROM with a replacement "disk image driver", but I have a suggestion for how that would be emulated.
In control mode, there would be a disk control menu (Control-D) for changing the disks (Control-D-F to change the emulated floppy disk to a different disk image or Control-D-R-F to remove the floppy disk from the emulated SCSI floppy disk controller, Control-D-0 to select a different disk image for the emulated hard disk in SCSI controller #0 or Control-D-R-0 to have it removed from SCSI controller #0 on the next reset of the emulated Macintosh Plus, Control-D-1 to select a different disk image for for the emulated hard disk in SCSI controller #1 or Control-D-R-1 to have it removed from SCSI controller #1 on the next reset, etc.)
The disk image for the floppy disk may only be 400KB (for emulating a single-sided single-density floppy disk in the floppy drive), 800KB (for emulating a double-sided double-density floppy disk in the floppy drive), or 1440KB (for emulating a high-density floppy disk in the floppy disk drive), in raw, Disk Copy 4.2 (unless "-sony-dc42 0" is set in the build system), or uncompressed Disk Copy 6.1 formats. However, if a Disk Copy 4.2 is selected for the emulated floppy disk and "-sony-sum-1 -sony-tag-1" is not set in the build system, Mini vMac will still patch the floppy disk driver in the ROM so the emulated floppy disk will be "locked" at that time.
How many SCSI controllers for hard disks are emulated varies on the "-hds N" option in the build system (which by default is "-hds 1"). When Mini vMac starts, all the SCSI controllers for the hard disks will be emulated, but with nothing attached to them, and the floppy disk drive will be emulated, but with no floppy disk in it.
However, the ROM will still be patched to add Mini vMac's "disk image driver" unless "-drives 0" is set (disabling Mini vMac's original style of disk images), although now the SCSI hard disk and floppy disk drivers will no longer be removed. "-hds 0" can be set in the build system to emulate no SCSI controllers for the hard disks and "-hds 0 -drives 0" can also be set, but the floppy drive will always be emulated.
Thank you for your suggestions for a user interface to control SCSI and accurate floppy disk emulation. But before a user interface can be implemented, the emulation must be implemented.
A good starting point for adding accurate floppy disk emulation to Mini vMac would be to peruse the “MESS” emulator source code for ideas. If anyone wants to work on this, I'd be quite likely to merge the result into the source code that I maintain. (As a compile time option.)
By the way: In a Macintosh Plus, floppy drives are controlled mostly through the IWM chip, and not the SCSI chip. Other early Macs are similar. Also, a Macintosh Plus has only a single SCSI chip, which can be used to connect up to 7 SCSI peripherals. And also, a real Macintosh Plus can only use 400K and 800K floppies. More advanced hardware is needed for 1440K floppies.
Began: Tue, 29 May 2012 04:17:03
I'm the user in korea but my minivmac doesn't worhask. My floppy disk has x mark on it. What can I do? Notice-I have dsk file and vMac.rom.
Probably there is a problem with your dsk file.
When a Macintosh Plus finds a bootable floppy disk, the picture on the screen of a floppy disk with a blinking question mark changes to a picture of a smiling Macintosh. If it finds a floppy disk that is not bootable, it instead displays a picture of a floppy with a blinking X mark, ejects the disk, and then goes back to displaying the picture of a floppy with a blinking question mark.
Follow the instructions on the Getting started page to get a bootable disk image. Make sure to extract the archive to get a file named “System Startup” and drag this file into the Mini vMac window, rather than attempting to boot from the “SSW_6.0.8-1.4MB_Disk1of2.sea.bin” archive.
Began: Sat, 26 May 2012 10:33:35
---------- Suggestion for http://minivmac.sourceforge.net/image.html ----------
Also, if you run the command "defaults write com.apple.DiskUtility advanced-image-options 1", you will then be able to create Disk Copy 6.1 images, or even Disk Copy 4.2 images in even the latest version of Mac OS X by setting the format in the "advanced options" when creating a disk image with Disk Utility to "Disk Copy 4.2", and the Disk Copy 4.2 images you create can then also be mounted with Mini vMac.
For me, using OS X 10.7.3, setting advanced-image-options works to add additional options in the Disk Utility "New > Disk Image from Folder" Command. However, trying to create "Disk Copy 4.2" images or "NDIF" images doesn't work, failing at the end with “Unable to create "my_image". (Invalid argument)”. I didn't think the underlying command line tools used by Disk Utility support these formats. What version of OS X are you using?
There's only one problem: Mini vMac does not allow the emulated Finder to write to Disk Copy 4.2 images, it only allows the emulated Finder to write to raw HFS disk images, while Mac OS X does not have anything built-in to read or write to raw HFS disk images (although MacFUSE with FuseHFS might be able to do that)
Recent versions of Mini vMac by default mount Disk Copy 4.2 images as read only. Full support for Disk Copy 4.2 images, mounting as read/write and handling tags and checksums, is available with the build system options “-sony-sum 1 -sony-tag 1”.
Began: Tue, 15 May 2012 15:56:45
Hi Paul...I love the Mini vMac.....I am currently writing a book about Dragon's Lair & Space Ace, and was FINALLY able to create archival images of the game from the original "Mac Plus/SE" disks! These do not exist on the internet today. The original Dragon's Lair on Mac says "Mac SE/PLUS - 1MB OF RAM". On a REAL Macintosh I had trouble running it on a Classic...I finally did get a machine to run it on, but STRANGELY even though it says 1MB, if you run on a 4MB machine you get "not enough memory". It's obviously poor programming that is causing the issue.
I am desperate to get this thing running so I can use some screen shots and so on (right now I literally have taken shots of a real screen and they don't look so great!).
I was wondering if there is a way (or could be a way) to limit the memory to 1MB or 2MB instead of 4 to see if these files will run?
Yes, with the “-mem” option to the build system.