Saluti.
> > IBM (VM/MVS mi sembra) fanno qualcosa di questo
> ...tipo *nix...
Ho trovato l'esatta citazione (non contiene il pezzo sui device driver, che
devo
aver trovato da un'altra parte - comunque e' quello che fa oggi VMware).
Tenete presente che 'now' significa 1996.
---Dr. Dobb's Journal: A Conversation With Michael Cowlishaw, by Jack Woehr
[March 1996]
[...]
DDJ: Can you briefly discuss the Virtual Machine (VM) operating system?
MFC: VM's main attraction...certainly back in the '70s and some would
say it still is...[is that it is] one of the best development
environments around. Every user sharing that machine has effectively
their own machine. It really was a series of PCs connected by a LAN,
except they all sat in one box, and everyone had a complete, simulated
virtual machine. It was a similar kind of development environment to
what people have today. Each person had their own personal single-user
operating system, with security since the boundary of each virtual
machine was very well defined. It was a delightful environment to use
and to program.
DDJ: Were you a VM enthusiast in its heyday?
MFC: I would say so, yes.
DDJ: Back in 1988, IBM was referring to a 386 running OS/2 as a
"programmable terminal." The mainframes were still so powerful that a
little box, even with a nifty GUI, didn't impress many IBM
technicians.
MFC: It's such a big company that you have different people working in
different places which are geographically and culturally widely
separated. People often work in isolation and don't have the
opportunity to spend time getting to know what's going on in other
corners of the corporation.
The AS/400 division was already very successful before many people in
IBM were aware of it or what it did or what its computers looked like
or how they worked. This is the case of the PC in IBM. People in
research were well aware of the potential, but people working on
mainframes, because they were working on mainframes, had no need for
PCs and therefore knew very little about them.
DDJ: I've heard IBMers say, "VM has outlived many of the executives
who tried to kill it." People don't always realize how much VM
influenced what we have today.
MFC: There is a parallel situation on personal-computer operating
systems, where the operating system is setting up a virtual machine
under which you run a copy of either the same or a different operating
system. You can set up a DOS box under OS/2, and it's such a complete
simulation of a PC you can actually boot DOS from a diskette into this
virtual machine. That's essentially what VM did...provide you with a
large number of 360/370 virtual machines, all running under the same
operating system. This is a pleasant environment, since every user had
their own "machine." It was also a good way of testing operating
systems, because you could run them under VM and test without bringing
down an entire machine, making it unavailable to users, until you had
done that testing.
The idea of virtual machines didn't originate with IBM, but [VM's
antecedent] CP67 was one of the earliest environments to use virtual
machines, and VM first brought them to their potential.
DDJ: The engineers who developed the Intel 80386 and its V86 mode must
have seen VM.
MFC: That's certainly true. VM took the concept of virtual machines to
considerably greater lengths than the people who originally thought of
it had in mind. VM did not stop at virtualizing the process unit, but
began simulating [mainframe I/O] channels and channel
adapters. Effectively, users had a complete system simulated, done in
a way which, thanks to various hardware innovations, exhibited great
efficiency. When you've got your time slice, you run as though you're
the native machine. It's not all simulation. These [are] concepts we
now see in OS/2 and so on.
[...]
---
Cheers,
alf
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