Block 4 Revision All Parts-1 PDF

QN   Question   Answer   1.   What  do  we  mean  by  The   The  term  ‘downtime’  refers  to  the  total  time  that  a  system  is   term  ‘downtime...

QN   Question   Answer   1.   What  do  we  mean  by  The   The  term  ‘downtime’  refers  to  the  total  time  that  a  system  is   term  ‘downtime’?   unavailable  for  use.   Every  hour  of  downtime  can  cost  an  organisation  a  lot  of   money.     What  sort  of  actions  or  behaviours  lead  to  downtime?   Before  I  discuss  my  findings,  see  what  you  can  find  out  by   searching  the  Weber       2.   What  are  the  main  causes  of   The  majority  of  downtime  is     downtime?   The  result  of  planned  maintenance  and  upgrades.       results  are  from  planned,  unavoidable  activities  such  as   data  backups,  database  reorganizations  and  hardware  and   software  upgrades.       3.   What  is  the  effect  of   In  today’s  e-­‐business,  systems  must  be  available  24/7.   downtime  on  today’s  e-­‐ Downtime  can  hurt  a  business  because     business?   information  is  not  available,  decisions  are  not  made,  orders   are  not  shipped,  funds  are  not  transferred  and  customers   cannot  interact  with  the  organization     in  short,  business  stops.     4.   Arnold  suggests  that  all   1. Backup  and  restoration       downtime  can  be  broadly   2. Hardware,  network,  operating  system  upgrades     classified  under  seven   3. Batch  processing  transactions     headings,  List  them.   4. Application  and  database  maintenance       5. Environmental  factors     6. Application  errors     7. Operator  and  user  errors       5.   What  is  the  main  idea  of  data   The  majority  of  small-­‐  and  medium-­‐sized  companies  outsource   centers   the  provision  of  computers  and  networks  to  commercial  data   centers;  large  warehouses  containing  several  thousand   servers,  special  cooling  equipment,  backup  generators  and   multiple  suppliers  of  power  and  internet  access.       6.   What  is  the  main  advantage   These  data  centers  can  spread  the  cost  of  the  specialized   of  data  centers?   equipment  and  staff  across  all  the  servers  and  incorporate     disaster  recovery  techniques  to  safeguard  customer   operations.     1        7.   What  are  the  main  causes  of   1) UPS  system  failure  (includes  battery  failure)     downtime  in  data  centers?   2) Accidental/human  error     3) Internal  environmental  control   4) Weather   5) Standby  generator  failure     6) IT  equipment  failure     8.   Define  Reliability.   The  ability  of  a  system  or  component  to  perform  its  required   functions  under  stated  conditions  for  a  specified  period  of   time.     9.   What  is  The  ‘mean  time  to   The  ‘mean  time  to  failure’  (MTTF)  is  a  statistical  measure  of   failure’  (MTTF)?   reliability  for  items  that  cannot  be  repaired.     It  is  based  on  testing  a  batch  of  items  over  a  short  period  of   time,  where  ‘short’  is  taken  to  mean  short  when  compared  to   the  expected  life  of  the  item     10.   How  to  calculate  the  mean     time  to  failure  (MTTF)  is:         11.   If  a  disk  drive  manufacturer     tests  a  sample  of  1,000  drives   by  running  them  for  a  period   of  1,000  hours  (just  over  41.5     days).  At  the  end  of  that   period  one  disk  drive  was   found  to  have  failed.  Calculate   The  MTTF.     12.   How  do  we  calculate  The     Annualized  failure  rate  (AFR)         13.   If  a  disk  drive  manufacturer   The  factor  8760  is  the  number  of  hours  in  one  year.   tests  a  sample  of  1,000  drives    (MTTF  of  1,000,000  hours)  the  AFR  =  0.876%.   by  running  them  for  a  period     of  1,000  hours  (just  over  41.5   days).  At  the  end  of  that   2      period  one  disk  drive  was   found  to  have  failed.  Calculate   The  AFR.     14.   How  can  we  use  the  AFR  to   as  follows:     estimate  the  performance  of   Number  of  drive  failures  =  number  of  drives  x  AFR.   the  disk  drives  in  a  server   For  example:     farm?   If  there  are  2000  disk  drives  we  can  expect  2000  ×  0.876,  or   approximately  18  drive  failures  per  year.     15.   What  is  the  main  problems   One  of  the  problems  with  MTTF  and  AFR  is  that  they  represent   with  MTTF  and  AFR   statistical  values  obtained  from  special  test  set  ups,  so  they   share  little  in  common  with  the  average  computer.   Furthermore,  attempting  to  calculate  the  MTTF  value  for  a   computer  from  the  MTTF  data  of  the  individual  components  is   not  a  simple  task.       16.   Define  Availability.   Availability  is  the  probability  that  a  service  or  system  is   available  to  be  used;     it  is  fully  functional,  performing  with  specified  limits,  and   delivering  the  appropriate  level  of  quality.     17.   Define  Availability  From  a   is  the  probability  that  a  system  is  working  when  required.   user’s  perspective   18.   How  do  we  calculate     Availability?     19.   How  do  we  calculate   Availability  If  a  system  has   not  yet  been  built     20.   What  is  Operational   Operational  availability  (Ao)  is  another  version  of  availability,   availability?   which  is  a  measure  of  the  availability  actually  measured  for  a     real  system     21.   How  do  we  calculate   Operational  availability?     22.   What  is  the  mean  downtime   The  mean  downtime  (MDT)  accounts  for  all  the  time  the   (MDT?   system  is  unavailable,  no  matter  the  cause.  It  will  include   downtime  for  corrective  maintenance  (fixing  a  problem),   preventative  maintenance  (change  a  noisy  fan,  software   update),  and  human  errors.     3     23.   What  is  Load  sharing?   Load  sharing  is  intended  to  improve  availability  by  sharing  the     total  workload  across  a  number  of  computers.     24.   What  is  Load  sharing  in  the   In  the  case  of  a  web  application  the  ‘nodes’  would  be  web   case  of  a  web  application?   servers,  each  with  its  own  local  storage  for  operating  system,   web  server,  content,  and  application  data,  and  the   combination  of  nodes  and  monitor  is  referred  to  as  a  ‘web   server  farm’.     Other  applications  might  comprise  multiple  file  servers,  print   servers,  DNS  servers;  hence  use  of  the  generic  ‘node’.     25.   What  is  ‘round-­‐robin’   The  ‘load  sharing’  monitor  provides  a  single  global  IP  address   scheduling?   for  the  web  server  farm  and  communicates  with  the  individual   web  servers  over  a  private  IP  network.     The  monitor’s  primary  function  is  to  decide  the  allocation  of   requests  amongst  the  member  nodes  based  on  how  busy  each   node  is,     or  it  may  be  a  simple  rotating  sequence  (also  known  as     ‘round-­‐robin’  scheduling).     26.   How  the  monitor  is   The  monitor  is  represented  by  another  computer  with   represented  and  what  should   appropriate  software,  but  it  could  also  be  a  smart  network   it  do?   switch  or  router.   The  monitor  must  track  the  health  of  each  node,  either  by   observing  the  flow  of  messages,  or  by  sending  a  ‘ping’  request   and  waiting  for  the  response.       27.   What  are  the  solutions  for   One  solution  to  the  user  data  problem  is  to  incorporate   handling  the  situation  of  a   cookies  into  the  application  so  that  the  data  is  held  by  the   node  that  fails  after   client’s  browser  and  returned  to  the  web  server  with  every   completing  a  single  user   request.     request?   Another  solution  is  to  add  some  form  of  shared  storage  to  the     architecture     28.   How  to  overcome  the   To  overcome  the  limitations  of  the  basic  configuration  requires   limitations  of  the  basic   that  the  nodes  are  more  tightly  integrated  and  somehow   configuration  of  the  nodes  of   share  their  current  state  across  the  entire  farm.  One  solution  is   load  sharing?   to  link  the  nodes  together  by  means  of  a  dedicated  ‘heartbeat’   network  and  a  special  heartbeat  monitor.       29.   What  are  the  additional  costs   The  higher  availability  of  the  heartbeat  configuration  comes   that  come  with  the  higher   with  additional  costs:   availability  of  the  heartbeat   dual  network  interfaces  in  each  node;  one  for   4      configuration?   application  data  and  one  for  the  heartbeat   An  additional  computer  to  function  as  the  heartbeat   monitor.     30.   Why  does  simple  load  sharing   Simple  load  sharing  offers  limited  availability  gains  because  of   offers  limited  availability   the  independence  of  each  node.     gains?   The  application  will  continue  to  function  with  multiple  node   failures,  failed  node  will  perceive  zero  availability     31.   What  do  we  mean  by  ‘scaling   The  real  benefit  of  load  sharing  is  what  is  termed  ‘scaling  out’;   out’   the  ability  to  process  more  requests  by  the  simple  addition  of   an  extra  node.       32.   Why  does  Load  sharing  can   Load  sharing  can  reduce  planned  downtime  because  a  single   reduce  planned  downtime?   node  can  be  updated,  or  backed  up,  in  isolation  while  the   application  continues  to  run  on  the  other  nodes.       33.   What  is  Cluster?   A  cluster  is  a  collection  of  independent  computer  nodes  that     function  as  a  single  ‘logical’  server  to  the  user.       34.   What  does  Cluster  allow  the   Cluster  allows  one  node  to  take  over  a  running  application   node  to  do?   without  the  user  being  aware  that  such  a  takeover  has   occurred.       35.   What  is  the  primary  goal  of   The  primary  goal  of  a  cluster  is  to  increase  availability  by   Cluster?   means  of  redundant  nodes.       36.   Clusters  typically  operate  in   In  the  active-­‐passive  configuration  one  node  is  actively  dealing   two  forms,     with  application  requests;  this  is  the  ‘active’  node  on  the  left,   active-­‐passive  and     labelled  System  A.  The  other  ‘passive’  node,  System  B,  is  in  a   active-­‐active.     standby  state  ready  to  take  over  in  case  of  failure.       Each  node  is  aware  of  its  current  role  in  the  cluster,  ensuring   that  only  System  A  responds  to  client  requests.       37.   How  the  two  forms  of   Heartbeat  messages  are  exchanged  between  the  active  and   clustering  interact?   passive  nodes  to  provide  the  monitoring  function.     Application  data  that  is  written  to  Disk  A  is  continuously   replicated  to  Disk  B  to  ensure  no  loss  of  data  should  System  A   fail.       Failure  of  the  active  node  forces  the  passive  node  to  assume   responsibility  for  running  the  application  through  a  process   referred  to  a  ‘failover’.     5     38.   What  is  the  additional  cost   The  gains  of  clustering  come  with  additional  costs:     that  come  with  Clustering?    Dual  network  interfaces  in  each  node,  one  for     application  data  and  one  for  the  heartbeat    Special  software  to  support  the  clustering  function   and  failover    Extra  system  administration  work  to  install,  configure,   and  monitor  the  cluster    High  cost  of  removing  single  points  of  hardware   failure  (power  supplies,  disks,  networks,  etc.).       39.   Explain  briefly  the  concept  of   One  of  the  strategies  adopted  by  organisations  that  require   fault  tolerance.   continuous  availability  is  fault  tolerance,  whereby  a  system  is   designed  so  that  it  will  continue  to  operate  in  the  event  of  a   single  hardware  failure.     The  general  technique  is  to  design  the  system  with  redundant   elements  and  extra  hardware  such  as  dual  power  supplies,   dual  network  interfaces,  and  RAID  disks.       40.   What  do  mean  by   The  techniques  for  increasing  availability  are  based  on  the   Virtualization?   traditional  deployment  model  of  one  application  per  server   farm  or  server  cluster.     Combining  these  techniques  with  the  typical  3-­‐tier  architecture   of  a  business  application  requires  a  lot  of  equipment.    This  is  a  very  expensive  deployment  model  in  terms  of   computing  equipment,  floor  space  (or  rack  space),  cooling   equipment,  power  consumption  and  personnel.       41.   Explain  briefly  the  term   The  term  used  when  multiple  server  applications  are   Infrastructure  consolidation   virtualized  to  run  on  a  single  hardware  platform.  So  instead  of     two  physical  computers,  one  to  host  a  file  server  another  to   host  a  print  server,  two  virtual  servers  are  created  to  operate   as  guests  on  a  single  computer.  Infrastructure  consolidation  is   the  main  contributor  to  reducing  the  total  cost  of  ownership   for  business  applications.       42.   Explain  briefly  the  term   The  term  used  to  isolate  applications  for  testing  or  to  enforce   Sandboxing?   a  high  level  of  security.  An  untrusted  application  can  be   combined  with  a  guest  OS  and  executed  within  a  virtual   machine  with  the  benefit  of  the  additional  protection  afforded   by  virtualisation.           6     43.   What  do  we  mean  by  Legacy   Many  virtualisation  solutions  support  operating  systems,  and   systems?   hence  applications,  that  cannot  be  executed  on  newer     hardware  platforms.  It  may  also  be  possible  to  emulate  older   peripherals  that  are  no  longer  manufactured.       44.   Explain  briefly  Recovery  in   an  image  of  a  virtual  machine  can  be  quickly  restarted  or   virtualization.   migrated  from  one  virtual/physical  computer  to  another  very   quickly.  Most  of  the  commercial  virtualisation  products   support  automatic  restart  or  migration  in  the  event  of  virtual   server  failure.       45.   Explain  briefly  Testing  and   By  combing  the  features  of  sandboxing  and  recovery  it  is   debugging  in  virtualization   possible  to  create  test  configurations,       take  images  of  the  configuration  at  different  stages  of   testing,  and     revert  to  a  saved  configuration  in  the  event  of  a  fault.       46.   Explain  briefly  the  concept  of   There  is  considerable  talk  about  ‘cloud  computing’  as  the   Clouds?   solution  to  provide  a  rapid  or  agile  response  to  the  changing   business  environment.     In  a  period  of  quick  growth  additional  computing  resources   (computers,  storage  or  network)  can  be  brought  on  stream   with  minimal  delay.  If  business  requirements  change  then  a   new  application  can  be  brought  into  play.       47.   Explain  briefly  the  concept   Infrastructure  as  a  Service  (IaaS)  provides  a  business  with  a   Infrastructure  as  a  Service   complete  set  of  computers  (servers,  firewalls,  load  monitors),   (IaaS).   network  links  and  storage  devices  on  which  to  host  their  own   software.     It  is  up  to  the  business  to  install,  update,  and  generally  manage   everything.  The  costs  are  typically  based  on  the  physical   equipment  utilised.       48.   Explain  briefly  the  concept   Platform  as  a  Service  (PaaS)  offers  a  business  a  computing   Platform  as  a  Service  (PaaS)   platform,  typically  a  virtual  server  and  guest  OS,  on  which  they   can  run  their  applications.  The  costs  are  typically  based  on  the   resources  used,  such  as  the  proportion  of  the  processor   utilisation,  the  amount  of  data  stored  on  disk,  or  the  number   of  bytes  transmitted  across  the  network.       49.   Explain  briefly  the  concept   Software  as  a  Service  (SaaS)  provides  a  business  with  an  entire   Software  as  a  Service  (SaaS)   application,  such  as  an  email  service  for  all  employees.     7      In  this  model  the  business  relinquishes  control  of  where  the   computing  equipment  is  located,  what  operating  system  is   used,  or  where  data  is  stored,  but  pays  a  fixed  monthly  charge   for  each  user.       50.   What  do  we  mean  by  Disaster   Disaster  Recovery  (DR)  means  putting  in  place  a  plan  that  will   Recovery  (DR)?   enable  a  company  to  recover  its  IT  systems  following  a   disaster,  or  enable  the  systems  to  continue  functioning   during  a  disaster.         51.   What  are  the  causes  of  the   The  cause  of  the  disaster     disaster?   may  be  environmental  (flood,  earthquake,  or  hurricane),     equipment  failure,     loss  of  power  or  communications,  or     a  security  incident  that  prevents  normal  operation.   52.   What  is  the  primary  goal  of   The  primary  goal  of  the  plan  is  to  reduce  the  impact  of  a   the  disaster  recovery  plan?   disaster  and  to  restore  all  systems  and  applications  to  a  fully   functional  state  as  quickly  as  possible.     Given  the  available  technology  it  is  possible  to  design  an  IT   solution  that  would  exhibit  no  loss  of  function  and  no  loss  of   data,  but  the  costs  would  be  very  high.           8      Block  4  Part  2   Revision   QN   Question   Answer   53.  Define  the  term  Project.   A  temporary  endeavor  undertaken  to  create  a  unique  product,   service,  or  result.     54.  Explain  briefly  the   A  new  field  of  study  is  Project  management,  with  its  own  set  of   concept  of  Project   tools  and  techniques  such  as  Gantt  charts,  PERT  (programmed   management.   evaluation  and  review  technique),  and  work  breakdown  structure.     55.  Discus  projects  in  terms   Opportunities  and  risks.     of  opportunities  and   The  opportunities  might  be  linked  to  launching  a  new  product,  or   risks.   creating  a  new  web  application.     By  undertaking  the  project  the  business  hopes  to  increase  revenue,   become  more  efficient,  and  make  a  profit.       At  the  same  time  the  project  presents  the  business  with  risks   because  it  may  not  be  completed  on  time,  it  may  cost  more  than   estimated,  or  it  may  not  produce  the  desired  result.       56.  What  are  the  common   The  common  features  of  IT  failures.   features  of  IT  failures?   1. A  lack  of  end-­‐user  involvement     2. Long  or  unrealistic  timescales   3. Vague  or  inadequate  requirements   4. Poor  change  management     5. Inadequate  testing  throughout  the  project       57.  Explain  briefly  the   Good  project  management  strives     concept  of  The  project   to  find  a  balance  between  a  project’s  requirements  and     plan.     quality  on  one  side  and  the  resources,       time,  and     risks  on  the  other.     The  proposed  solution  is  typically  expressed  in  the  form  of  a  project   plan  that  documents  what  is  to  be  done,  who  will  do  it,  and  when  it   will  done.     58.  Draw  a  diagram  that   The  Waterfall  lifecycle  model  known  as  linear  software   shows  the  stages  of  the   development  cycle’  each  phase  must  be  completed  before  the  next   Waterfall  lifecycle  model.   phase  can  commence       9     QN   Question   Answer         59.  Write  three  of  the  Pros   Pros  (advantage)   and  Cons  of  the  Waterfall   1) Time  spent  in  the  early  phases  reduces  the  chance  of  errors   lifecycle  model.   in  later  phases   2) Promotes  a  top-­‐down  approach  to  decomposition  leading  to   sub-­‐goals  that  can  serve  as  project  milestones.   3) Provides  clear  boundaries  between  phases  that  are  orderly   and  predictable.     Cons  (disadvantage)   1) Reliance  on  documentation  outputs  at  each  phase  can   hinder  communication  and  lead  to  slow  development.   2) There  is  a  long  delay  between  the  start  of  a  project  and  the   delivery  of  functional  software.   3) Sequential  phases  restrict  opportunities  for  parallel   development.   60.  Explain  briefly  the     The  V-­‐model:   V-­‐model   1. Phases  can  overlap  at  the  edges     2. All  testing  activity  has  been  pulled  out  into  a  separate   sequence  of  phases.     3. The  phase  ‘detailed  design  and  production’  has  been  split   into  three  phases:  design,  code,  and  test.     4. The  phases  after  ‘production’  are  bent  upwards  to  create   the  V-­‐shape;  creating  the  separate  lines  of  activity  labelled   ‘project  definition’  and  ‘project  integration’.         10     QN   Question   Answer       61.  Define  a  project  plan.   A  formal,  approved  document  that  defines  how  the  project  is   executed,  monitored  and  controlled.     62.  What  is  the  main  aim  of   The  project  plan  aims  to  define  :   project  plan?   the  objectives  of  the  project  and     the  process  by  which  the  work  will  be  managed  and     delivered  on  time  and     within  budget.       63.  What  are  the  main   The  purposes  of  project  plan  are:     purposes  of  project  plan?     1. The  project  objectives     2. The  scope   3. Partnerships   4. The  outputs   5. The  resources   6. The  team.   7. The  estimate   8. The  risk  assessment.   9. Other  elements:  quality  goals,  Channels  of  communication       64.  Discuss  the  importance   Goals  and  targets  of  projects  must  be  monitored  to  ensure  that  the   of  Projects  Monitoring.   project  gets  completed  on  time  and  within  budget       65.  What  do  we  mean  by   Such  as  the  delivery  of  an  item  of  equipment  or  completion  of   Project  milestone?   some  tests,  and  provides  the  means  to  compare  the  actual   performance  to  the  planned  performance.     11     QN   Question   Answer   It  is  to  leave  some  time  to  take  corrective  action  in  case  of  any   problems.     66.  What  do  we  mean  by   A  project  gate  (or  stage  gate)  represents  a  point  in  the  project  when   Project  Gate?   all  work  stops  to  await  a  decision,    I  say  yes  or  no   for  example  a  gate  at  the  end  of  the  user  requirements  phase   provides  the  opportunity  to  terminate  the  project  if  the  user   requirements  cannot  be  adequately  defined.     Another  use  of  the  project  gate  is  at  sign-­‐off  points,  when  the  ‘client   has  to  confirm  their  acceptance  of  some  output.       67.  What  are  the  common   The  three  most  common  metrics  employed  are:   metrics  employed  to   1. Time:  compares  the  estimated  duration  to  the  actual  time  taken   monitor  projects?   to  complete  a  work  package.       2. Cost:  compares  the  estimated  cost  to  the  actual  cost  of   completing  a  work  package   3. Deliverables:  compares  the  estimated  time  and  cost  to  create  a   deliverable  with  the  actual  time  and  costs.       68.  Explain  briefly  the   Gathering   Gathering  stage  of   The  gathering  stage  is  intended  to  elucidate  the  raw  ideas  about   requirement.   what  the  ‘solution’  should  provide  in  terms  of  important  features     and  how  it  will  interact  with  other  parts  of  the  business.     69.  Explain  some  of  the   One  of  the  techniques  employed  is  to  interview  stakeholders  about   techniques  of  Gathering?   their  specific  needs.     If  the  objective  of  the  project  is  to  improve  an  existing  process,  then   it  is  important  to  understand  how  the  current  process  operates   and  where  it  falls  short  of  user’s  needs.     70.  Explain  briefly  the   The  refining  stage  converts  the  raw  ideas  into  something  more   Refining  stage  of   structured,  such  as  a  business  process  or  a  prototype  website.     requirement.       It  is  important  that  stakeholders  are  given  the  opportunity  to  review   the  proposal  to  ensure  it  meets  their  needs.  Ideally,  stakeholders   should  ‘sign  off’  on  the  requirements  in  order  to  lock  down  the  set   of  features  to  be  provided.       71.  What  are  the  main  the   One  of  the  challenges  of  the  user  requirements  phase  is  satisfying   challenges  of  the  user   conflicting  features  or  functions.  Individual  stakeholders  will  have   requirements  phase?   different  perspectives  on  what  the  project  should  achieve  and  hence   what  the  priorities  should  be.     12     QN   Question   Answer   72.  Explain  briefly  MoSCoW   MoSCoW  prioritisation.  The  acronym  ‘MoSCoW’  represents  four   prioritization  concept.   levels  of  priority  expressed  by  the  words  ‘Must’,  ‘Should’,  ‘Could’,   and  ‘Won’t’.     The  claimed  value  of  the  MoSCoW  method  is  that  the  use  of  words   offers  a  clearer  meaning  to  stakeholders  when  they  come  to   prioritise  features  and  functions         73.  Explain  briefly  the   Must  –  the  project  must  provide  the  feature  or  function;  a  ‘Must’   MoSCoW’  levels.   feature  is  non-­‐negotiable  and  if  not  delivered  then  the  project  is  a   failure.       Should  –  the  project  should  provide  the  feature  or  function  if  at  all   possible;  a  ‘Should’  feature  is  important,  but  if  time  is  short,  it  could   be  postponed  for  a  future  delivery.  The  project  still  has  value   without  these  features.       Could  –  the  project  could  provide  the  feature  or  function  if  it  does   not  affect  anything  else;  a  ‘Could’  feature  would  be  useful  to  have  if   it  does  not  cost  too  much  or  take  too  long  to  develop,  but  it  is  not   central  to  the  project.       Won’t  –  the  project  won’t  provide  a  feature  or  function  this  time,   but  will  be  needed  in  the  future,  where  it  may  be  upgraded  to  a   'Must'.  Knowing  what  the  future  features  and  functions  are  helps  to   ensure  that  a  proposed  solution  does  not  preclude  them.       74.  Explain  briefly  the  term    ‘functional  quality’,  meaning  that  a  piece  of  software  is  ‘fit  for   ‘functional  quality’.   purpose’  and  delivers  the  functional  requirements.       Some  texts  use  the  term  ‘external  quality’  to  refer  to  quality   ‘external  quality’   characteristics  seen  by  an  external  user.    The  primary  method  of  assessing  functional,  or  external,  quality  is   by  testing  that  the  software  fulfils  each  of  its  requirements.     75.  Explain  briefly  the  term   Another  interpretation  of  quality  is  of  ‘structural  quality’  or   ‘structural  quality’   ‘internal  quality’  that  relates  to  how  well  the  software  was   ‘internal  quality’   produced.       76.  List  the  characteristics  of   (ISO)  describes  software  quality  in  terms  of  eight  characteristics  :   software  quality  which   1. Functional  suitability,     are  described  by  ISO.   2. Performance  efficiency,     3. Compatibility,     13     QN   Question   Answer   4. Usability,     5. Reliability,     6. Security,     7. Maintainability,   8.  Portability.     77.  List  the  Consortium  for  IT   The  Consortium  for  IT  Software  Quality  (CISQ)  has  defined  five   Software  Quality  (CISQ)   structural  quality  attributes  essential  for  a  piece  of  software  to  have   structural  quality   business  value   attributes  that  are   1. Reliability   essential  for  a  piece  of   2. Efficiency   software  to  have  business   3. Security     value.   4. Maintainability     5. Size     78.  List  the  points  that   the  quality  plan  address  the  following  points  :   should  be  addressed  in   1. identification  of  appropriate  quality  standards  and  the   the  quality  plan   methods  to  satisfy  them   2. procedures  to  ensure  quality  standards  are  followed  and   identification  of  those  responsible  for  quality  assurance   activities   3. monitoring  of  project  outputs  to  determine  compliance  with   the  quality  plans  and  to  provide  opportunities  for   improvement.     79.  List  standards  and  tools   In  the  case  of  web  applications  there  are  numerous  standards  and   that  can  contribute  to   tools  that  can  contribute  to  quality.     quality  of  web   For  example,  the  W3C  standards  for  HTML  and  CSS  and  the  WCAG   applications.   guidelines  can  be  combined  with  output  from  validation  tests  that   acts  as  evidence  of  compliance     80.  What  are  the  methods   The  resource  and  duration  estimates  can  be  derived  using  the   that  are  used  in  the   methods  listed  below:   resource  and  duration   1. Use  historic  data:  look  back  at  similar  tasks  and  use  the  time   estimation  of  projects   it  took  as  the  estimate  for  the  current  task.  Many  companies   collect  data  about  performance  for  just  this  purpose.   2. Ask  a  friend:  asking  a  co-­‐worker  is  a  good  option  when  the   task  is  unfamiliar  to  you.   3. Weighted  average:  include  three  estimates  labelled  ‘best’   ‘worst’,  and  ‘most  likely’.  These  three  are  combined  as  (best   +  4  ×  most  likely  +  worst)  ÷  6  to  give  the  desired  value.   4. Management  tax:  once  your  estimate  is  obtained  increase  it   by  a  fixed  percentage  to  allow  for  non-­‐productive  activities   such  as  meetings,  phone  calls,  email,  etc.     14     QN   Question   Answer     81.  Explain  briefly  the  term   Projects  have  some  degree  of  uncertainty  as  to  the  outcome,  for   Risk  management.   example,  Will  it  be  completed  on  time  and  on  budget  and  will  it   fulfill  the  requirements?     Understanding  and  controlling  this  uncertainty  is  termed  risk   management  and  it  involves  putting  in  place  procedures  to  help   identify  and  assess  project  risks,  along  with  strategies  to  minimize   the  impact  of  any  risks  that  arise.       82.  What  are  the  two  main   There  are  two  important  points  to  observe.     important  points  to   The  first  is  that  a  specific  risk  may  not  materialise,  for  example,  it  is   observe  in  Risk   possible  that  all  testing  is  completed  even  though  there  was  a  risk   management.   that  some  testing  would  be  delayed  or  skipped.       The  second  point  is  that  the  consequence  of  a  risk  may  not  have  a   significant  impact  on  the  project,  for  example,  progress  in  the  latter   stages  of  development  may  recover  lost  time  as  the  team  develop   their  knowledge  of  the  development  tools.       83.  List  the  strategies  that   There  are  several  generic  strategies  that  could  be  employed  such  as:     could  be  employed  in     Risk  Management.   1. Eliminate  or  avoid  the  risk  by  not  doing  things  or  doing  them     a  different  way   2. Reduce  the  likelihood  of  the  risk   3. Reduce  the  impact  of  the  risk   4. Stop  the  project     5. Share  the  risk  with  a  partner   6. Accept  the  risk       84.  What  is  the  final  stage  of   The  final  stage  of  risk  assessment  is  to  combine  all  the  information   risk  assessment?   that  has  been  gathered  into  a  risk  management  plan  that  highlights   the  most  significant  risks,  outlines  the  mitigation  strategy,  and   assigns  responsibility  for  monitoring  the  risks.       85.  Explain  the  term  risk   It  is  a  separate  document,  known  as  the  risk  register,  is  used  to  track   register   changes  in  the  level  of  each  risk  and  to  record  actions  are  taken  to   manage  the  risks  as  the  project  progresses.             15      Block  4  Part  5   Revision   QN   Question   Answer   86.  What  do  we  mean  by   Testing  has  become  a  core  element  of  web  application   System  testing?   development  and  it  is  the  mean  by  which  we  demonstrate  that   the  solution  fulfils  the  requirements  and  that  we  have  exercised   due  diligence  in  its  creation.       87.  List  with  explanation  what     to  test  in  the  system.   1. Functionality  testing:  aims  to  verify  that  web  pages  are   functional.     2. Usability  testing:  aims  to  ensure  that  the  application  is   easy  to  use   3. Accessibility  testing:  aims  to  ensure  the  application  is   accessible  to  all  users   4. Interface  testing:  aims  to  ensure  the  correct   interoperation  of  the  web,  application,  and  database   servers.   5. Compatibility  testing:  aims  to  ensure  that  the  application   functions  correctly  regardless  of  browser,  operating   system,  or  hardware  type  or  version.   6. Performance  testing:  measures  the  ability  of  servers  and   network  to  respond  to  user  demand.   7. Security  testing:  aims  to  ensure  the  application   implements  authentication  and  authorization  controls  and   is  not  vulnerable  to  attacks.   8. Regression  testing:  is  any  type  of  software  testing  that   seeks  to  uncover  defects  that  recur  as  an  unintended   consequence  of  program  changes;  the  software  is  said  to   have  regressed  to  the  previous  defective  state.     88.  Explain  briefly  the  role  of     V-­‐model  lifecycle  provides  a  useful  framework  to  explore  the   V-­‐model  in  testing.   management  of  testing.  The  left-­‐hand  part  of  the  V-­‐model   corresponds  to  the  design  of  the  application,  expanding  on  the   level  of  detail  within  each  phase  of  definition.     89.  What  is  the  importance  of   The  creation  of  tests  plans  is  an  integral  part  of  project  definition   creating  tests  plans?   that  provides  verification  of  the  design  and  helps  to  ensure  an   application  fulfils  its  requirements.     16     QN   Question   Answer   90.  What  is  required  to  mange   Managing  each  phase  of  testing  requires:   each  phase  of  testing?   identification  of  what  is  to  be  tested,     who  does  the  testing,  and     how  the  results  of  the  tests  are  collated  and  communicated.     91.  Who  is  supposed  to   Large  projects  often  have  a  dedicated  test  team  who  prepare  and   conduct  the  testing?   execute  the  tests  and  track  defects.     Smaller  projects  typically  share  the  work  amongst  the   development  team.       92.  What  is  the  main  role  of   Unit  tests  are  intended  to  verify  the  execution  of  small  pieces  of   Unit  test?   code,  such  as  functions  or  object  methods,  before  the  function  or   object  is  combined  with  other  units  into  a  larger  functional   element.     93.  What  are  the  main  points     or  a  typical  web  application  the  unit  test  phase  should  cover  the   that  can  be  included  in   following  items:   Unit  test  for  a  typical  web    HTML  validation   application?    CSS  validation    Forms  (as  components  combining  multiple  units)    Internal  hyperlinks   Client-­‐side  objects  and  functions  (data  validation)    Server-­‐side  objects  and  functions    Database  queries.     94.  Can  the  author  of  the  unit   The  author  of  the  unit  should  not  prepare  the  tests  or  execute   prepare  the  tests  or   them;  to  avoid  any  tendency  to  bias  the  test  toward  the  known   execute  them?   features  of  the  unit.       95.  What  is  the  main  role  of   Integration  tests  are  intended  to  verify  that  individual  units  work   Integration  test?   together,  which  for  the  typical  web  application  means  testing   functionality,  usability,  browser  compatibility,  and  accessibility.     96.  What  is  the  main  role  of   Usability  tests  are  conducted  to  identify  any  design   Usability  test?   inconsistencies  or  usability  issues  in  the  user  interface  and   content  areas  of  a  website’s  pages.     97.  Explain  briefly  the  potential   Potential  sources  of  error  may  include:   sources  of  error  when    Navigation  errors  –  a  user  fails  to  locate  functions,  takes   conducting  Usability  tests.   too  many  keystrokes  to  complete  a  task,  or  fails  to  follow   the  recommended  sequence  of  web  pages.    Presentation  errors  –  failure  to  locate  important   17     QN   Question   Answer   information  on  the  page,  failure  to  select  the  correct   action  due  to  labelling  ambiguities.    Control  usage  problems  –  incorrect  use  of  buttons,  tabs   and  toolbars,  or  failure  to  enter  data  into  the  correct  field.       98.  What  is  the  main  role  of   Functional  tests  are  typically  designed  around  specific  tasks,   Functional  test?   such  as  user  registration,  catalogue  search,  or  payment  for  goods   and  will  highlight  integration  problems  between  the  client  and   server.       99.  What  are  the  main  role  of   System  tests,  or  end-­‐to-­‐end  tests,  are  intended  to  verify  the   System  tests?   interoperability  and  performance  of  the  application  in  its  final   configuration  and  to  verify  integration  with  other  hardware  and   software  systems  that  support  the  wider  business  functions.       It  provides  the  opportunity  to  verify  and  document  the   procedures  to  install  and  configure  servers,  set  up  user  accounts,   populate  the  database  with  test  data-­‐sets,  and  test  backup  and   recovery  procedures.       100.Where     should  we  conduct   Ideally  system  tests  are  conducted  on  a  dedicated  set  of   system  test?   equipment  that  matches  the  performance  and  configuration  of   the  final  production  servers.       101.When    should  we  conduct   By  the  time  system  testing  commences  all  Unit  and  Integration   system  test?   testing  should  be  complete  to  the  point  that  there  is  a  stable   version  of  the  web  application  to  test       102.What  a  re  the  goals  of   Once  a  stable  configuration  of  the  test  environment  has  been   performance  test?   created  performance  testing  can  commence.     The  goals  of  performance  tests  is  to  establish:    That  the  system  meets  planned  response  times  for  a  given   load    That  the  system  remains  stable  under  high  load    An  estimate  of  the  sustainable  peak  load       103.What  d   o  we  mean  by  the   Where  the  term  ‘load’  represents  the  number  of  simultaneous   term  “LOAD  “  when  we   users  accessing  the  web  application.     talk  about  high  load  or     peak  load?   104.Explain     briefly  with   Load  test:     example  the  load  test.   Describes  a  performance  test  during  which  a  well-­‐defined  load  is   18     QN   Question   Answer   applied  to  the  application  to  determine  the  response  time  for   individual  functions.   For  example,  the  requirements  may  specify  that  with  a  load  of  300   users  the  response  time  to  a  log-­‐in  request  should  not  exceed  10   seconds  or  that  a  search  for  a  product  within  a  catalogue  should  not   exceed  15  seconds.       105.Explain     briefly  Stress   Stress  test:   test  and  its  main  goal.    Describes  a  test  to  assess  the  performance  of  the  application  when   the  load  exceeds  the  expected  usage.   The  goal  is  to  ensure  that  the  system  remains  reliable  and  stable   even  though  errors  may  arise,  such  as  dropping  a  user  part-­‐way   through  a  purchase  transaction.   106.Explain     briefly  Capacity   Capacity  test:     test.   Describes  a  performance  test  intended  to  provide  an  estimate  of   the  maximum  number  of  users  the  application  can  support  reliably.       107.How  do     we  conduct   During  the  test  the  load  is  increased  until  the  performance   Capacity  test?   becomes  unacceptable;  either  because  the  response  times  become   excessive  or  the  server’s  processor  utilization  exceeds  a   predetermined  limit.     108.Explain     the  goals  of   Acceptance  or  user  acceptance  testing  is  the  final  phase  of  testing   Acceptance  or  user   in  the  V-­‐model  lifecycle.   acceptance  testing.   The  goal  of  this  phase  is  to  verify  that  the  web  application  fulfils  the   ‘user  requirements’  that  were  established  at  the  outset  of  the   project  and  thereby  reduce  customer  dissatisfaction  because  the   application  doesn’t  do  what  was  promised.     109.Who  should     conduct  the   It  is  the  client,  not  the  developer,  who  should  perform  the   acceptance  test?   acceptance  tests  against  the  test  environment.     110.What  a  re  the  critical   Critical  areas  for  client  involvement  are:   areas  for  client    Function:  (Application  fulfils  functional  requirements)   involvement  in  testing.    Usability:    (User  can  get  to  information  quickly  and  easily,   on-­‐screen  instructions  are  understandable  and  number  of   steps  to  complete  a  task  is  appropriate)   Work  flow:  (Sequence  of  web  pages  of  an  application  match   the  underlying  process  work  flow  (e.g.  the  steps  are  in  the   correct  order).   111.What  is     the  difference   Once  all  the  tests  have  been  identified  they  must  be  executed  and   between  Manual  or   the  outcomes  recorded.     19     QN   Question   Answer   Automated  testing?   manual  execution:  a  user  sits  in  front  of  a  computer  and  enters     data,  search  terms,  or  follows  hyperlinks  and  records  the   Tow  type  of  testing   outcome  of  each  test.     Manual     Automated   The  alternative  is  automated  execution  whereby  a  program  or     script  runs  a  number  of  predefined  tests  and  saves  the  results.     Such  as  whitebox,  blackbox.   Knowing  the  best  way  to  perform  the  tests  can  be  as  important  as   the  tests  themselves.     112.What  d   o  we  mean  by  Test   Test  environments  means  the  configuration  of  clients,  servers,   environments?   and  network  used  to  conduct  the  tests.     Three  distinct  environments  are  required  namely:     Development,  Test,  and  Production.     113.What  d   o  we  mean  by  the   The  development  environment  is  a  mixture  of  clients  and  servers   development   that  will  support  developers  during  the  early  phases  of  the   environments?   project.     Unit  testing  and  version  control  is  the  responsibility  of  each   developer.       114.What  is     the  use  of  Version   Version  control  will  store  all  the  code,  tests  and  documentation   control?   associated  with  each  project.     115.What  is     the  use  of  Access   Access  controls  ensure  that  each  develope