Recent content by David Cook

Just the application and destination file. This surprised me as well. If you compare the ratio of LC floppy / LC HD (=78%) to 512K floppy / 512K HD (=73%), it suggests that the numbers are about right. The CPU decoding and CRC calculation seem to be limiting factors at this MHz.

Using Floppy Emu in HD20 mode, System 3.2, and with/without a 32K ram cache, the performance is only a little better. I then tried a RAM disk with similar results. It seems that the CPU is more of a bottleneck than the drive.

Thank you @Realitystorm I had not seen those articles. They reinforce what I've noticed so far: Some OS operations monopolize the CPU and cause negative side effects. AppleTalk is the example in your linked articles. I've also noticed that TickCount is signficantly slowed down by floppy access...

I've written a little application to transfer files from one Mac to another over a serial cable (peer to peer). I'm using the XModem protocol for the file transfer, and BinHex 4 for the encoding of the file contents. These choices were made for compatibility, not performance. As I'm getting...

Thanks to an eBay link from @RepairManiac, I was able to purchase one of the SIMM removal tools. Here are some close-up pictures. It is made out of a really high-quality plastic. The grip feels heavy, though. Weighted with a metal insert? The adjustment slide with the single screw lacks...

Hi Adrian, How's your digital basement? In an interesting twist of fate, last August I learned how to differentiate the video output signals for the Novy board by watching one of your videos. I was able to get my Novy board to display on both monitors. However, as I have not paid a recovery...

What a fantastic picture! I'm envious of your Mac tool collection.

A quick note on getting the Classic to boot from the ROM disk in Mini vMac: 1. Perform a custom variation build from the website of Mini vMac targeting the Classic. https://www.gryphel.com/c/minivmac/var_serv.html 2. Put a copy of the Classic ROM (from...

Here are the eight versions of pre-6 MacsBug that I located. To use one, rename it to be just plain 'MacsBug' without the date or version number. Then, drag that into your System Folder. Those brave enough to use this on a MFS disk need not worry about whether it is in a folder or not. The...

I've scoured the internet, my floppy treasure trove, and even a ROM to locate the following eight versions of pre-6 MacsBug. I found three versions of MacsBug that were originally titled Maxbug because it filled the screen (as opposed to the original MacsBug / xMacBug that only shows ten...

Ordered!

Does anyone have a copy of MacsBug 5.1? I'm trying to debug an application on the Macintosh 512K, and I would like the latest version that ran on that machine. "MacsBug Debugger for Macintosh. Copyright Apple Computer 1982-1986. Originally by Motorola. Adapted to Lisa/Mac by Rich Page...

Sometimes I pay too much for a machine just to solve some mysteries. Recently, a Macintosh II with a hard drive labeled A/UX came up for auction. The seller did not show photographs underneath the tray, so I was taking a chance on the motherboard being undamaged and having its socketed chips...

I ran across this thread as I searched for a replacement speaker for my Macintosh 512K. It is a Regal 63 ohm 0.25W. Interestingly, my other 512K has a Samsung brand. I scrounged my junk box and found a 32 ohm speaker. It works fine, but is quieter (as expected). However, the speaker does not...

Very cool