| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 127.1 | Feasible? Yes, Recommended? No | KOKO::DAVIS | Sandy Davis | Thu May 05 1988 17:43 | 23 |
| I believe Model 204 is an inverted list DBMS from Computer Corporation
of America (CCA) of Cambridge, MA. Since it is inverted list,
conversion is probably possible although far from systematic. While
idealy one would never convert a data base, redesign is preferable,
in reality many customer choose the conversion route to save money.
Rarely do they save money however because conversions generally
increase maintenance costs instead of bringing in savings.
A straight conversion is particularly undesireable when changing
from one technology (i.e., Inverted List) to another (i.e., Relational)
since most data bases have been designed and optimized for the original
technology and taking advantage of the new technology's features
is awkward. Now I'll get down off the soap box...
Data Conversion should be fairly straight forward. Applications
would require more work. But if they choose to do a straight conversion
relational can be used in a similar fashion to inverted list, if
they choose not to take advantage (initially) of the SET-AT-A-TIME
capabilities of relational over the RECORD-AT-A-TIME method employed
by their current system.
Sandy
|
| 127.2 | It depends... | BANZAI::BISSON | | Fri May 06 1988 21:01 | 22 |
|
I used to work on layered products for Model 204 at CCA. I agree
that conversion of the data is possible, but the difficulty of the
task will depend upon how "relational looking" the design is. An
inverted list system, especially Model 204, will allow the database
designer almost total freedom in choosing a data model.
The major problem that you may encounter will be in converting
the application itself. Model 204 applications are built in either
"User Language", a propietary/procedural query language, or in a
third generation language like FORTRAN or COBOL with "Host Language
Interface" or HLI calls.
The answer is that the feasibility of the conversion "depends".
It depends on the design of the database and of the application, and
on the language in which the application has been built. If I were
in the position I would want to see the schema and application before
recommending conversion.
Adrien Bisson
|
| 127.3 | More 204 questions | SNOC01::ANDERSONK | DOD Australia believes SNA is OSI compliant | Tue Feb 14 1989 14:35 | 16 |
| We have another customer in Canberra running MODEL 204 on AMDAHLs
and they are looking for a lot of stuff that we can do re workstations,
windows, imaging, paperless office etc.
1. How would you advise selling a VMS and Rdb environment into a shop
that will otherwise convert to an all-IBM environment with OS/2
front ends running PC 204?
2. Obviously there is no interconnect or migration strategy for MODEL
204. If it takes us so long to get a DB2 VIDA interconnect together
then I guess a 204 VIDA link is not very likely. What do we offer
the customer as a migration path off the mainframe?
3. Does anyone have any competitive info on PC 204?
Whimper (I dont feel good about this one)
|