Review of Module1
1
BINA RAMAMURTHY
[email protected]
B.Ramamurthy
5/16/2013
Items
2
 Please complete exercise #1, activity #1, and exercise #2;
enclosed are those slides for your convenience
 Lab1 formal statement is available; lets review it.
 Form groups of 2: We need to pair up people who have
accounts on Buffalo machine to people who do not have
accounts as of now.
 Claim your ubit account: http://www.buffalo.edu/ubit/service-guides/accounts/your-ubitnameaccount/getting-started-with-your-account/claiming-your-account1.html
 Lets review the interrupt levels from a sample processor as
indicated by Sharat.
 Lets review the details of thread programming. This skill is
required for understanding Embedded Xinu multi-threaded
kernel.
B.Ramamurthy
5/16/2013
Exercise#1
3
 Lets identify 10 embedded systems, realtime systems and
realtime/embedded system
 I will begin with Arduino Uno
Example
B.Ramamurthy
Type; justification
5/16/2013
Activity#1
4
 Identify some ECUs in a modern automobile and a
possible qualitative requirement.
Example
B.Ramamurthy
Justification
5/16/2013
Exercise #2
5
 Automatic vending machine money counter
 Embedded system (Rs.5 counter)
 Coins: 1, 2 and 5 rupees: Think of your example
2
S1
S3
1
5
1
5
S2
2
2
S4
5
1
1
2,5
1
2
S0
5
S5+
S5
B.Ramamurthy
5/16/2013
Operating System
6
 An general purpose OS can be defined by its functions as:

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
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Process/execution manager (Process: unit of schedulabilty)
Interface manager
Resources / hardware manager
Memory Management unit (MMU)
IO manager
File system manager
 Each of these units have their own set of “exceptions” or
interrupts defined
 Result is a well-defined set of interrupts and handlers for
addressing exceptional situations.
B.Ramamurthy
5/16/2013
Operating system Modular View
7
Virtual Mem
Comm.
Prmtvs
Application
Server
User
Processes
Shell
Hardware +
interrupts
Directories
File sys.
Process +
primitives
Web
Server
Devices
Application
Clients
B.Ramamurthy
Web
Clients
5/16/2013
Interrupt Levels (contd.)
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Class 3 — Context Management
1 FCD Synch. HW Free Context List Depletion (FCX = LCX).
2 CDO Synch. HW Call Depth Overflow.
3 CDU Synch. HW Call Depth Underflow.
4 FCU Synch. HW Free Context List Underflow (FCX = 0).
5 CSU Synch. HW Call Stack Underflow (PCX = 0).
6 CTYP Synch. HW Context Type (PCXI.UL wrong).
7 NEST Synch. HW Nesting Error: RFE with non-zero call depth.
Class 4 — System Bus and Peripheral Errors
1 PSE Synch. HW Program Fetch Synchronous Error.
2 DSE Synch. HW Data Access Synchronous Error.
3 DAE Asynch. HW Data Access Asynchronous Error.
Class 5— Assertion Traps
1 OVF Synch. SW Arithmetic Overflow.
2 SOVF Synch. SW Sticky Arithmetic Overflow.
Class 6 — System Call
SYS Synch. SW System Call.
Class 7 — Non-Maskable Interrupt
0 NMI Asynch. HW Non-Maskable Interrupt.
B.Ramamurthy
5/16/2013
Interrupt Levels
9
Class 0 — MMU
0 VAF Synch. HW Virtual Address Fill.
1 VAP Synch. HW Virtual Address Protection.
Note: For VAF and VAP, see also MMU Traps.
Class 1 — Internal Protection Traps
1 PRIV Synch. HW Privileged Instruction.
2 MPR Synch. HW Memory Protection Read.
3 MPW Synch. HW Memory Protection Write.
4 MPX Synch. HW Memory Protection Execution.
5 MPP Synch. HW Memory Protection Peripheral Access.
6 MPN Synch. HW Memory Protection Null Address.
7 GRWP Synch. HW Global Register Write Protection.
Class 2 — Instruction Errors
1 IOPC Synch. HW Illegal Opcode.
2 UOPC Synch. HW Unimplemented Opcode.
3 OPD Synch. HW Invalid Operand specification.
4 ALN Synch. HW Data Address Alignment.
5 MEM Synch. HW Invalid Local Memory Address.
B.Ramamurthy
5/16/2013
How to build “robust” systems?
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 Identify potential faults and exceptions
 Handle them deterministically by implementing
fault/exception/interrupt handlers
 Also have a default handler for those unknown
anomalies
 In fact, a robust system will have a set of exception
handlers, several types for each major module of a
system.
B.Ramamurthy
5/16/2013
Some Logistics
11
B.Ramamurthy
5/16/2013
Status of connectivity to Buffalo
12
 Our first step is to get connectivity to CSE systems
 Access timberlake.cse.buffalo.edu using putty (secure shell)
 Next step is to access nexos.cse.buffalo.edu from
timberlake

This will allow us to do kernel programming
 Final step is to get full access to UB resources (if that
is possible without a 16-digit ID)
B.Ramamurthy
5/16/2013
Student Portfolio
13
 We will collect all the work that you do for this class
as a portfolio.
 This will be a part of your evaluation.
 Also once CSE account is ready, you can submit all
the work to the CSE submit feature (somewhat like a
backup or cloud)
 You can compile all the items you created in this
class and assemble this portfolio.
B.Ramamurthy
5/16/2013