retrocomputing
Also, I learned the hard way that even though the 5150, XT, AT, & pre-PS/2 IBM clones all have physically compatible keyboard sockets (5-pin DIN, just like MIDI sockets), the 5150 & XT use an incompatible protocol, so AT-style keyboards won't work unless they have an XT-mode switch.
BTW, that line after the syntax error message isn't one I typed in again. It printed the line & put the cursor at the beginning so I could edit it.
Also, I miss messy full-screen program editors like that. Press Enter, the line your cursor's on is executed. If the line starts with a number, it's inserted in your program, automatically sorted numerically, replacing the same-numbered line if it already exists.
You'd think that a boxed set of disks still in shrinkwrap would be best protected from damage. Nope. this is the underside of a DOS 3.3 boot disk that sat unused & protected in a tyvek sleeve, in a special pocket, in a 3-ring binder, in a box, under shrinkwrap for 31 years. Look at the mylar disc visible through the oval access hole.
But the weird thing is both original disks were fine in my 286's 1.2 MB drive the one time I put them in there, & by coincidence the one command I ran to exercise them both was diskcopy, giving me a full duplicate of both disks, & both copies work just fine in my XT.
It's a good thing neither IBM nor Microsoft put copy protection on their DOS boot/install disks.
Welcome to IBM PC-XT (5160) Cassette Basic in ROM, required for the earliest PC-DOS BasicA even though the cassette port & header pad both ceased to exist after the 5150.