An improved preemption delay upper bound for floating non-preemptive region

In embedded systems, the timing behaviour of the control mechanisms are sometimes of critical importance for the operational safety. These high criticality systems require strict compliance with the offline predicted task execution time. The execution of a task when subject to preemption may vary significantly in comparison to its non-preemptive execution. Hence, when preemptive scheduling is required to operate the workload, preemption delay estimation is of paramount importance. In this paper a preemption delay estimation method for floating non-preemptive scheduling policies is presented. This work builds on [1], extending the model and optimising it considerably. The preemption delay function is subject to a major tightness improvement, considering the WCET analysis context. Moreover more information is provided as well in the form of an extrinsic cache misses function, which enables the method to provide a solution in situations where the non-preemptive regions sizes are small. Finally experimental results from the implementation of the proposed solutions in Heptane are provided for real benchmarks which validate the significance of this work.

Job phasing aware preemption deferral

Preemptions account for a non-negligible overhead during system execution. There has been substantial amount of research on estimating the delay incurred due to the loss of working sets in the processor state (caches, registers, TLBs) and some on avoiding preemptions, or limiting the preemption cost. We present an algorithm to reduce preemptions by further delaying the start of execution of high priority tasks in fixed priority scheduling. Our approaches take advantage of the floating non-preemptive regions model and exploit the fact that, during the schedule, the relative task phasing will differ from the worst-case scenario in terms of admissible preemption deferral. Furthermore, approximations to reduce the complexity of the proposed approach are presented. Substantial set of experiments demonstrate that the approach and approximations improve over existing work, in particular for the case of high utilisation systems, where savings of up to 22% on the number of preemption are attained.

Le Free-Holder, ou L'Anglois jaloux de sa liberté , essais politiques . Traduction de l'anglois

Titre original : The Free-Holder, or Political essays

Second Welland Canal - Book 1, Survey Map 1 - Entrance, Lock 1 and Port Dalhousie

Survey map of the Second Welland Canal created by the Welland Canal Company showing the areas in and around Port Dalhousie and Grantham Township. Identified structures associated with the Canal include Lock 1, Lighthouse, Lighthouse Keeper's House, East and West Piers, Harbour, Waste Weir, Store House, Collector's Office, Collector Assistant Office, Lock Tender's House and the new towing path. Features of the First Welland Canal are noted in red ink and includes the old Harbour, old Lock 1, old towing path and the original bed of the Twelve Mile Creek. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks and businesses are also identified and include streets and roads (ex. Lock Street and Colonel Clark's Cattle Road), Alex Muir's Dry Dock, RandJ Laurie Flouring Mill, R. Laurie and Company Grist Mill, A. Morrison Saw Mill, Johnson's Tavern, a store and a church. Properties and property owners of note are: Concession 1 Lots 21 and 22, John Christie, John Clark, N. Pawling, William Pawling, W. Carter, G.A. Clark, J. Maven, Mrs. Wood, James Drabble and J. Woodall.

Second Welland Canal - Book 1, Survey Map 2 - Lock 1 and Port Dalhousie

Survey map of the Second Welland Canal created by the Welland Canal Company showing the areas in and around Port Dalhousie and Grantham Township. Identified structures associated with the Canal include Lock 1, East and West Piers, Collector's Office, Lock Tender's House and the new towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks and businesses are also identified and include streets and roads (ex. Road to St. Catharines, Side Line, Old Road to Port Dalhousie, Road to Niagara), the Welland Railway and its structures (ex. freight sheds, wood shed, raised platform, elevator, cranes, water tank, turn table, and passenger station), G. A. Clark's Wood Yard, Clark's Wood Office, Alex Muir's Dry Dock, Donald, Andrews and Ross' Dry Dock, RandJ Laurie Flouring Mill, R. Laurie and Company Grist Mill and A. Morrison Saw Mill. A New Road to St. Catharines is featured in red ink. Properties and property owners of note are: Concession 1 Lots 19, 20 and 21, John Christie, and John Clark.

Second Welland Canal - Book 1, Survey Map 3 - Old Lock 2 in Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township near Port Dalhousie. Identified structures associated with the Canal include the new towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old Lock 2, old towing path and the original bed of the Twelve Mile Creek. Local area landmarks are also identified and include streets and roads (ex. Side Line and Old Road), four unnamed bridges, and a tree stump along the old towing path. A New Road to Port Dalhousie is featured in red ink. Properties and property owners of note are: Concession 3 Lots 21, 22 and 23, Concession 4 Lots 21, 22 and 23, Jabez Johnson, Adam Gould, Peter Weaver and Samuel Wood.

Second Welland Canal - Book 1, Survey Map 9 - Lock 2 in Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township sometimes referred to as the Welland Vale. Identified structures associated with the Canal include Lock 2, several weirs, and the Lock Tender's House. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old towing path and the Old Canal itself. Local area landmarks and businesses are also identified and include streets and roads (ex. Side Line and Old Road to Port Dalhousie), J. C. Clark's Ice House, J. L. Ranney Store House, a burnt mill, barrel shed, a building leased to Michael Kerrins, and a number of unidentified structures (possibly houses or cabins) belonging to D. Cain, R. Cain, W. Weaver and W. Huddy. A New Road to St. Catharines is featured in red ink. Properties and property owners of note are: Concession 5 Lots 20, 21 and 22, Concession 6 Lots 20 and 21, Thomas Adams, John Gould, George Rykert, Theophilus Mack, William H. Merritt, J. L. Ranney, and the Board of Works.

Second Welland Canal - Book 1, Survey Map 12 - St. Catharines and Lock 4

Survey map of the Second Welland Canal created by the Welland Canal Company showing the Town of St. Catharines. Identified structures associated with the Canal include Lock 4, Hydraulic Race, floating tow path, and the Canal waterway itself. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include streets and roads (ex. Geneva Street, St. Paul Street, Queenston Street, Niagara Street and Mill Street), C. Phelp's Grist Mill and Store House, Stinson's Distillery, and several unnamed bridges. Properties and property owners of note are: Concession 6 Lot 16, J. R. Benson, Calvin Phelps, J. Hudson, David Gray, A. Roberts, Mrs. McDonell, J. S. McDonell, T. B. Wragg, J. Donaldson, W. Barr Jr., C. L. Hall, G. Ward, Ridout Bros and Co., and the St. Catharines Grass Co.

Second Welland Canal - Book 1, Survey Map 14 - St. Catharines and Lock 5

Survey map of the Second Welland Canal created by the Welland Canal Company showing the Canal along the eastern edge of the Town of St. Catharines. Identified structures associated with the Canal include Lock 5 and the towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include bridges, streets, and roads (ex. Queenston Street, St. Catharines Macdamized Road and Suspension Bridge), a Pond, a number of unnamed bridges, Stinson's Distillery, and R. Collier's Saw Mill. Properties and property owners of note are: Concession 6 Lots 14 and 15, R. Collier, W. Gillespie, Orson Phelps, W. Chase, M. Bryant, John Soper, Winsor Chace, John Berryman, John Boyle, J. Madigan, B. F. Reynolds, W. Smaill, F. Stinson, G. Ward and Mrs. Soper.

Second Welland Canal - Book 2, Survey Map 14 - Lock 26 and Allanburgh

Survey map of the Second Welland Canal created by the Welland Canal Company showing the canal as it passes through the Village of Allanburgh. Identified structures and features associated with the Canal include Lock 26, a Guard Lock, Lock Tender's House, the New Cut, waste wear, and the towing path. Parts of the old canal are indentified and include Old Lock 36 and 37, and the Old Cut. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include streets and roads (ex. Holland Road, Centre Street, Falls Street, Canal Street, and Clifton Street), Allanburgh Hotel, Rannies Store, Wright and Duncan Grist Mill, A. Vanderburgh Saw Mill, W. Pennock Shingle Factory, John Harper Tavern, a very delapitated Grist and Saw Mill, store house, a shanty, and a number of other structures - some of which are identified by their owners: A. Vanderburgh, W. Wright, C. Brent, and H. Mussen. Properties and property owners of note are: Lots 118 and 119, Captain Creighton, and William H. Merritt Jr. A number of small properties labeled 1 through 39 are present and of these 6 - 15 are reserved for a Mill Site and are outlined in red. Several other pieces of land are outlined in blue and belong to: W. B. Hendershot, P. Finlay, W. Wright, and L. Leslie. There is also a piece of land reserved for hydraulic purposes.

Second Welland Canal - Book 3, Survey Map 11 - Aqueduct Lock and Canal along Chippewa Creek in Thorold

Survey map of the Second Welland Canal created by the Welland Canal Company showing the canal as it crosses Chippewa Creek in the Thorold Township near Welland. Identified structures and features associated with the Canal include the towing path, the old canal, the aqueduct lock, the new aqueduct, and the waterway itself. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include roads (ex. Aqueduct Road, and Road to Weland), Chippewa Creek, the Spoil Bank, a house and a barn. Properties and property owners of note are: Lots 239, 247, and 248, Joseph Burgar, and Smith Shotwell.

Sketch of Canal Lock 2

Sketch of canal lock 2 by S.D. Woodruff. This is a hand drawn sketch, n.d.

Clippings - Road Allowances, Lock 2 Bridge, Toronto Railway Company, St. Davids' History

Clipping regarding the original road allowance which was part of Mr. Woodruff’s property, n.d. Clipping regarding the Lock 2 Bridge. This is a letter to the editor of the Journal from Calvin Phelps of Lockport, Nov. 13, 1889. Clipping entitled “Settled beyond a Dispute”: a letter to the Editor of the Star from J. G. Currie regarding the road allowance in the 5th Concession of Grantham, Nov. 16, 1889. Clipping entitled “That Old Road Allowance” which is a rebuttal to Mr. Currie’s letter, [1889] 2 newspaper clippings regarding: “Reg. vs. Toronto Railway Company”. These 2 articles are glued to a piece of paper. Beneath the newspaper articles is the name M. Chambers, Nov. 18, 1898. Notes regarding the clippings are enclosed with the articles. These notes and written on the back of “Pattison, Collier and Shaw Barristers, Solicitors, Etc.” stationary (notes are 2 pages, handwritten), Nov. 18, 1898. Clipping entitled “History on the Site: St. Davids’ Students Learn Lessons where Events Occurred” (2 copies), n.d.

Lock of Hair - Charles Band

Lock of hair from Charles Band – an envelope within another envelope containing Charles Band’s hair. This is from a haircut for Granny’s anniversary. The writing of the envelope says “Pussy’s hair” Nov. 21, 1922.

Four Leaf Clover & Lock of Hair

Envelope containing a four leaf clover “for luck” and little Margaret’s hair (9 mos. old), Sept. 3, 1937.