Retrocomputing questions and answers


Is it safe to turn on a 40-year old TRS-80?

My father is a retired programmer. When I was in high school in the late 1970s, he purchased a TRS-80 model 1 (on which I learned to program in BASIC). At some point in the early 1980s it, together with various accessories, was put in a box and stored in ....

Luna Luna: 02 February 2022


Starting a multi core CPU as single core

Is it possible to use a system with a modern, multi-core CPU with older operating systems that only support single core operation? Is this something that needs to be set in the BIOS? Does it depend on the CPU, the BIOS, the OS, or something else? ....

Victoria Victoria: 01 February 2022


Microsoft C 6, far pointer, cast to int, warning C4047

Trying to access one byte in memory using segment/offset, like this union REGS in, out; struct SEGS segs; int v; char _far* p; ... int86x(...,&in,&out,&segs); p = ( << 16) + out.x.bx + 4; v = (int)*p; and get "warning C4047: different levels of indirection" (and the value of v ....

Jack Jack: 01 February 2022


Was imported software for computers as common as it was for consoles?

In the 90s and in Western countries, you were able to buy import software for pretty much every video game system, for instance, Super Nintendo, Mega Drive, PC Engine, PlayStation and so on. To run them, you generally needed either an adapter for cartridges or a modchip for CD-ROMs. But ....

Levi Levi: 01 February 2022


Why are there three different settings in the [Paths] section of MSDOS.SYS?

In Windows 9x, the MSDOS.SYS configuration file contains a section whose contents usually look like this: WinDir=C:\WINDOWS WinBootDir=C:\WINDOWS HostWinBootDrv=C Both WinDir and WinBootDir point to the Windows installation directory, which usually is C:\WINDOWS, and HostWinBootDrv points to the drive letter containing it. Having distinct settings suggests that potentially these could ....

Charlotte Charlotte: 31 January 2022


How does the serial port on the RC2014 get addressed?

I see on the schematic ( that /M1 and A7 go to CS0 and CS1 respectively. As I recall, both of these need to be high for the chip to be selected. And A6 goes to CS2, which needs to be low for the chip to be selected. And of ....

Alice Alice: 31 January 2022


Zilog's relationship with Mostek

The Wikipedia page on Mostek (, one of the original fabricators of Z80 chips, includes the following claim: When Vin Prothro, President, and L. J. Sevin, Chairman of the Board, discovered that Zilog had modified the recipe for Z80 chips to keep the yields low, thereby buying Zilog time to ....

Josiah Josiah: 31 January 2022


Windows 98 fails to install with 'Windows Setup requires 7340032 by' error in console

If you install Windows 98 from CD-ROM by first booting from a start-up floppy (such as a Windows 98 Startup Disk) and run setup.exe, it will inform the user that it is going to check the hard disks, and then it is possible that you will get a strange, half-formed ....

Charlotte Charlotte: 31 January 2022


Why did the VIC-20 and C64 have only 22 and 40 columns when the earlier PET had 80 column text?

When I was a kid, the "real" computers in movies looked so cool with that 80-column monochrome green text. My first computer was a VIC-20 it always felt very "toy" to me because of its 22 columns of fat text. Later my C64 was a better 40 columns, but still ....

Jade Jade: 31 January 2022


Did the Timex Sinclair 2068 and the Sinclair ZX Interface 2 use totally different hardware and software techniques?

Sinclair released an add-on for the Spectrum called the ZX Interface 2 ( that provided joystick ports and a cartridge slot. It wasn't successful and only a few cartridges were ever produced. In the US, Sinclair partnered with Timex to make the not very successful Timex Sinclair 2068 (, which ....

Hannah Hannah: 31 January 2022