Tyus Carver, Josh Clark, Dock O'neal, Kyle Sekellick, Jeremy Smith,

Overview of Embedded Systems  System A way of working, organizing or doing one or many tasks according to a fixed plan, program, or set of rules an arrangement in which all its units assemble and work together according to the plan or program  Embedded System: a system that has computer–hardware with software embedded, or fixed, in it

Overview continued..  Main components of Embedded Systems Hardware Main application software Real-time operating system supervising the application software  Classification of Embedded Systems Small Scale, Medium Scale, and Sophisticated Embedded Systems

Embedded History  1958 Jack Kiby invents the first integrated circuit at Texas Instruments  1959 planar transistor makes commercial production of integrated circuit's possible  1960's brings revolutions in integrated circuits  Developments in integrated circuit technology leads directly into microprocessors

History continued  Intel comes up with idea of reprogrammable microprocessor in  In 1971 the Intel 4004 chip is released First microprocessor Requires additional components  1974 Texas Instruments releases the TMS 1000 First chip to be targeted at embedded systems

Embedded Systems Hardware  Three General Categories Standardized processor Configurable rocessor Full-Custom processor

Standardized Processor  Microcontroller Derivatives of yesterday’s leading edge general purpose processors Programmable Slow clock-speed, little memory, and unchangeable to consumer  Systems on a Chip Much more complex Supporting circuits Off-The-Shelf or Custom

ConfigurableProcessor  PLD  PAL  PLAs

Full-Custom Processor  Application-specific integrated circuit (ASIC) Behavioral perspective (purpose) Structural perspective (which components provide desired behavior) Physical Perspective (how to place on the chip)

Embedded System Software  Embedded System Memory vs. general purpose computer memory Two types of memory distinction ○ rarely employ virtual memory ○ Variable and diverse from memory architectures  Can contain RAM, ROM, and flash memory  ISRs (interrupt service routine) are used in invoke various signal on the pins of the processor

Embedded System Software Cont.  Memory space is distinguished between program memory, writeable data memory, and read-only memory. Read-only contains constants and literals used by the embedded program, embedded systems usually only run one program so ROM can be used, this protects from accidental overwrites. The designer determines the placement of the program code Stack and heap are often implemented in static RAM to eliminate DRAM refresh cycles. Heap may or may not be used Dynamic memory may be avoided because it memory cleanup incurs overhead that can cause unpredictable access delays Memory leaks are very bad as most embedded systems run for months or years without every rebooting. A tiny leak can eventually cause a catastrophic system meltdown.

Embedded System Software Cont.  Responsiveness Differs in access to hardware and events are clearly defined ○ Hard and soft real time systems  If you’re late you’re wrong Evaluation of responsiveness ○ Context switch time or interrupt latency

Embedded System Software Cont.  Memory Footprint Uses small and efficient kernels ○ Come with a scheduler, interprocess communications manager, etc.  Use standard IEEE POSIX A standardized UNIX specification that now includes real-time extensions Dozens of operating systems are available, QNX being the most popular

Embedded System Software Cont.  Development Requirements must be spelled out in detail ○ Use of formal languages  Schedules are carefully planned and monitored  Hard to break into chunks for individual teams.

Embedded System Software Cont.  Major Problems involved Global variables ○ Have both positive and negative draw backs Unstructured code ○ Is spaghetti code the way to go? Events ○ Impossible to determine order of events Debugging ○ BDM, JTAG, NEXUS, ICE

Security of Embedded Systems  Embedded systems are vulnerable to several types of attacks and attackers: Class I: Low threats that target existing weaknesses Class II: Insiders with training and more resources Class III: Specialists with little to no limit on resources

Security of Embedded Systems Cont.  These systems need to be secure multiple ways: Private Users (User identification) Secure Network Access (A verified device) Secure Communications (Authenticating peers) Secure Storage Content Security (Content restrictions) Availability (Minimizing downtime)

Security of Embedded Systems Cont.  Developers also have some challenges faced when trying to make their systems secure: Processing Gap: A device’s processing power Battery Gap: A device’s battery capacity Flexibility: A device’s ability to house several types of security Tamper Resistance: A device’s durability Assurance Gap: A device’s uptime Cost: A device’s manufacturing and retail cost  Some Solutions: Symmetric Ciphers (Secure Keys) Asymmetric Ciphers (Secure and Public Keys) Hashing Algorithms (Encrypted Messages)

References  Grand, Joe. " usa-04/bh-us-04- grand/grand_embedded_security_US04.pdf." Black Hat. Web. 22 Apr  "Historymicro." Historymicro. Web. 22 Apr  Null, Linda, and Julia Lobur. "Embedded Systems." The Essentials of Computer Organization and Architecture. Sudbury, Mass.: Jones and Bartlett, Print.  RAVI, SRIVATHS, and ANAND RAGHUNATHAN. "Security in Embedded Systems: Design Challenges." Georgia Tech. Web. 22 Apr