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Comment by seanc | Hacker News Reader

Not true! Floppies had viruses too. Even back in the 80's.

https://en.wikipedia.org/wiki/Michelangelo_(computer_virus)

He did claim "reformat", which tends to delete these viruses. Albeit to clarify you'd also need to clear the boot record, which is not something all DOS format tools would do.

Compare that to USB devices, which contain data that survives to all host-initiated methods of erasure and which may in fact not be storage devices at all; i.e. fake keyboard/mouse presses et al.

I think parent refers to the fact that if you insert a floppy disk and reformat it without running anything on it, it's safe.

This is not true for USB drives, as USB controllers can be programmed to re-insert a virus or fry the system at any time in the future.

Not true for floppies, either. To reformat the boot sector, include the /S switch.

FORMAT /S

Yeah, but they would not autorun anything. If you forgot them inserted and rebooted, however...

Michelangelo and similar viruses only activate when you boot from the disk it's on. Insert a disk with Michelangelo in a running system, then format the disk (make sure you overwrite the boot sector), all OK.

The operating systems of the time didn't have any autoplay functionality that could be exploited by viruses. I guess in theory viruses could have exploited things like buffer overflows in the OS code that reads the file allocation table or directories, but I've never heard of such a thing, and Michelangelo and similar boot viruses certainly were not that advanced.

Autoplay is as at least as old as Windows 3.1. A file called "autoexec.bat" would be executed on mounting, IIRC (not a Windows-person myself).

Not at all. Autoplay is new to the win 95 shell. And the idea of "mounting" is absolutely alien to a DOS system which can't even tell when a disk is inserted or not on a device.

DOS' shell would run autoexec.bat when booting but only the one from the boot volume.

That's autorun.inf, not autoexec.bat.

Back in the 80's few machines had hard drives, and often only one floppy. So if you put your disk in the drive and fired up the machine then bang, you were infected.

Also, lots of machines with hard drives were configured to boot from floppy by default. Few floppies had working boot sectors, so most people never noticed. Until they put an infected disk into A:, turned on the computer and saw chaos ensue.

Yes, that's right, that's why I said to insert it in a running system.

There were plenty of Macintosh viruses that spread this way, such as the WDEF/MDEF/CDEF families.

> Infects the Desktop file used by the Finder. … Spread through sharing disks, as every Mac disk includes a Desktop file. It is not necessary to run a program to spread this virus; simply mounting the disk is enough for it to infect the Desktop file of every disk mounted on the Mac.

https://lowendmac.com/2015/classic-mac-os-viruses/

I recall a few on my c64, back in the early 80s for sure.

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