18 Aug
1998
18 Aug
'98
5:19 a.m.
The last VT103 I configured went to RCS/RI and it was tested with a
11/23B in it.
< Well, I always thought that RSX and RSTS/E were far
< better of with more memory. Also, with V5.0 of
< RT-11, the availability of 4 MBytes and a VM: was highly
< useful - not needed, but very nice. Of course, until
< recently, DEC memory boards were so expensive that
< more than 1/4 MByte was not worth while in any case as
< opposed to SIMMs with the PC. However, a half MByte
< board (M8067) is now so inexpensive that it is no longer
< a problem.
I have systems with 256k and more, with a hard disk having a ramdisk is
cute but not required. Doing a a non hacked system is far easier.
Also 4mb of DEC qbus ram (1mb cards) will severely load the BA11S boxes
I have never mind the Vt103 PS, I've done it. That box with 11/73, RQDX3,
DLV11j, LAV-11, RLV12, RXV211 and 4 memory cards overloaded the 340watt
PS! The disks were off seperate power. Heck the two RD52s and RX33
requires a 70W power supply.
< > A good package is a 11/23, 256kram, DLV11j, RQDX3, BDV11.
< > That gives you 4 serial ports, full memory without backplane mods,
< > RX50/RX33 floppy and MSCP hard disk (RDxx) and the BDV terminates
< > the bus plus supplies some of the desireable boots (no mscp).
<
< What hardware did you use to connect the RQDX3 to the RX50/RX33
< floppy drives? In general, I found the floppy to be far too slow
< and if I was jumping up the an RX33, for the same price (at current
< cost for a hard drive) I would prefer at least an RD51.
The BA123 disk distribution card M9058. I use both RX33 and RX50.
generally stuff for RX50 being more common I use that more though the
rx50 will read/write RX50. for a hard disk 30mb Quantum D540s (RD52)
as they are fast and reliable plus plenty of space. RD50, RD51, RD31,
RD32 are not worth the effort as they are slow or old.
< You can always power the disk drives with an auxiliary power
< supply from a PC. In that case, you can even have 2 hard
< drives and 2 floppies. Otherwise, with just the one hard
Danger Will Robinson. External MFM drives on seperate power means YOU
MUST POWER OFF THE DRIVE FIRST THEN THE SYSTEM. Failure to do so will
mean writing garbage to the disk at what ever track it's on. The fix is
easy reformat and reload the disk... Not something you want to do. It's
ok if they both power off at the same time. Many PC power supplies have
a switched outlet that can power the VT103.
< drive (under the tube), it is indeed on the edge of the PS
< if the VT103 supplies all the power. One other option I
Don't, the drives generate serious heat and that spot is poorly cooled.
< mentioned is that a SIGMA RQD11-B (MFM controller)
< uses about the same power as an RQDX3, but has BOOT
< ROMS. As a result, you can use just the dual 11/23 and
< no BDV11. Then there is enough internal power to run
That's handy but the disk is 30-37W and it's the back breaker. Going
with over 256k of ram invites the same problem. If you want a big system
get a decent box with adaquate cooling and power and use that.
< YES!! If run for a long time. But for short demos of
< an hour or less, the VT103 was highly effective. Most
< individuals who were familiar with the VT100 did not
< recognize the VT103. So when the demo was given,
< the first reaction was to ask about the computer - they
< saw only a VT100. We used to say that we had substituted
< clever squirrels inside the VT100 instead.
there were three differnt similar systems. PDT11/130 with TU58, VT103
and a MDS11-A. The latter two woere similar but slightly different
backplane.
< I even heard that someone had re-wired the backplane
< to allow a MicroVax II (ABCD slots for the first 2).
It would be easier to use a H9276 or other correct backplane in the
available space. Still the microvaxII and memory eats power in
a serious way.
< Now imagine if DEC had sprung the VT103 on the
< PC world as a PC at PC prices with a 150 watt power
Try more like a 300W ps to build want your talking about.
< supply (and a bigger fan) to easily allow hard drives under
< the tube. And later, had gone to the MicroVax II as
Why not the pro350/380, a well designed PDP-11 desktop system.
If you want a tiny vax get a VS2000 or one of the 3100 series.
< a standard option. The 10 year late DEC PCs would
< have been initially based on the PDP-11 and could
10 years late???? The Pro350 was in the market the same time as the PCxt
and the PDT11/150 predates the PC by a few years.
< then have used the VAX. The only thing lacking was
< a pricing model to compete with the XT and the AT
The PRO350 competed with a loaded PCxt with CGA color and a hard disk for
very similar $$$$. for similar $$$ inthe PCxt space was the Rainbow100.
< I understand that a total of 32 solder connections are
< required. I once saw the re-wired backplane. It
< seemed to have been done with wire-wrap wire
< since the solder points were so small.
The ones I did had longer WW pins on the backplane (BDV-11s) and I used
a standard bussing strip I have. Saves megga pain WW'ing a backplane.
Allison