I tried to boot NetBSD 1.5.1 boot1.fs and boot2.fs diskettes, but the second
diskette hung.  Last lines were

mainbus0 (root)
isa0 at mainbus0
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fif0
com1 at isa0 port 0x2f8-0x2ff irq 4: ns16550a, working fif0
wdc0 at isa0 port 0x1f0-0x1f7 irq 14
wd0 at wdc0 channel0 drive 0: <SAMSUNG PLS-31274A>
wd0: drive supports 16-sector pio transfers. lba addressing
wd0: 1213 MB, 2466 cyl, 16 head, 63 sec, 512 bytes/sect x 2485728 sectors
wd0: drive supports PIO mode 3, DMA mode 1

Sometimes the last line didn't show.  When I booted the installation kernel with
DOSBOOT.COM from DR-DOS 7.03 with EMM386.EXE not loaded in CONFIG.SYS, I got one
additional line:

wdc1 at isa0 port 0x170-0x177 irq 15

before hanging.

When I booted the generic kernel with DOSBOOT.COM, I got this plus three more
lines before hanging:

vga0 at isa0 port 0x3b0-0x3df iomem 0xa000-0xbfff
wsdisplay0 at vga0: console (80 x 25, vt100 emulation), using wskbd0
lpt0 at isa0 port 0x378-0x37b irq 7

Text was green on black, and the last line was black except for one little white
rectangle in column 1 (screen width 80 columns).

Is there any way to capture the dmesg to a file that would survive when the boot
fails?  Something like dosboot netbsdi > dosboot1.log
which I don't think would work here?

I downloaded NetBSD-INSTALL.gz and NetBSD-GENERIC.gz and saved as NETBSDI.GZ and
NETBSDG.GZ since I am in DR-DOS 7.03.  Then I decompressed with
C:\UNTGZ095\UNTGZ32 -d NETBSDI.GZ NETBSDI  and
C:\UNTGZ095\UNTGZ32 -d NETBSDG.GZ NETBSDG

Upper case or lower case makes no difference with file names in DOS.

I was successful booting OpenBSD 2.9 installation diskette, though I couldn't
go far since I didn't download the stuff to install.  I was also able to boot
Linux Slackware 8.0 using N_5380.S kernel, though the system hung when I tried
to mount the CD-ROM (must be a bug in the driver, since this hang occurs every
time when I try to mount the CD-ROM).

This is on my current old computer, essentially a preview, where I downloaded
NetBSD, but none of the packages/pkgsrc, in two sessions using a DOS-based
scripted FTP.  Modem is 56K on 0x2e8, IRQ 5.  CPU is Cx486DX2-S at 66 MHz.
RAM is 20 MB.  Hard disk is 1213 MB, partitions are (all primary):

1:  65 cylinders (just under 128 MB) FAT16 for DR-DOS 7.03, drive C:
2: 130 cylinders (just under 256 MB) FAT16, DOS data, drive D:
3: type 83 (Linux native, not formatted, not in use)
4: type 82 (Linux swap, not in use, 30 cylinders (?))

NetBSD would be installed in the space taken by partitions 3 and 4, which would
be deleted.

I have floppy drives A (1.44 MB) and B (1.2 MB).  I have Trantor T130B SCSI with
internal Texel 2x CD-ROM and external Iomega Zip 250.  Zip 250 is in doubtful
condition, appears on the way down.  I heard a click on the Zip 250 while
trying to boot the NetBSD installation diskettes, presumably meaning the boot
diskettes probed that port.