COLUMN J: the number of bits with the value 1. Since columns C through I contain either the number 1 or the number 0, a
simple SUM(C:I) yields the number of bits with the value of 1.
10.6 The ABC Company is considering the following options for its backup plan:
1. Daily full backups:
• Time to perform backup = 60 minutes
• Size of backup = 50 GB
• Time to restore from backup = 30 minutes
2. Weekly full backups plus daily incremental backup:
• Same time, storage, and restoration as above to do a weekly backup on Friday,
plus
o Time to perform daily backup = 10 minutes
o Size of daily backup = 10 GB
o Time to restore each daily backup file = 5 minutes
3. Weekly full backups plus daily differential backup:
• Same time, storage, and restoration as above to do a weekly backup on Friday,
plus
o Time to perform daily backup = 10 minutes first day, growing by 5 minutes
each day thereafter
o Size of daily backup = 10 GB first day, growing by 10 GB each day
o Time to restore differential backup file = 5 minutes first day, increasing by
2 minutes each subsequent day
Which approach would you recommend? Why?
Total
100 Minutes
90 GB
35-50 Minutes
Full Weekly Backup
60 Minutes
50 GB
30 Minutes to restore
last full backup
Daily Differential
Backup
70 Minutes (10 minutes
first day, increasing by 5
minutes/day – but on
Friday, just make the full
weekly backup) =
10+15+20+25=70
100 GB (10 GB for
first day, 20 GB for
second day, etc. but on
Friday, just make the
full weekly backup)=
10+20+30+40=100
5- 11 Minutes (5
minutes first day, 2
minutes more each
subsequent day but on
Friday, just make the
full weekly backup)
Total
130 Minutes
150 GB
35-41 Minutes
10.7 Which control(s) would best mitigate the following threats?
a. The hours worked field in a payroll transaction record contained the value 400
instead of 40. As a result, the employee received a paycheck for $6,257.24 instead
of $654.32.
b. The accounts receivable file was destroyed because it was accidentally used to
update accounts payable.
c. During processing of customer payments, the digit 0 in a payment of $204 was
mistakenly typed as the letter “O.” As a result, the transaction was not processed
correctly and the customer erroneously received a letter that the account was
delinquent.
d. A salesperson mistakenly entered an online order for 50 laser printers instead of
50 laser printer toner cartridges.
e. A 20-minute power brownout caused a mission-critical database server to crash,
shutting down operations temporarily.
f. A fire destroyed the data center, including all backup copies of the accounts
receivable files.
a. After processing sales transactions, the inventory report showed a negative
quantity on hand for several items.
b. A customer order for an important part did not include the customer’s address.
Consequently, the order was not shipped on time and the customer called to
complain.
c. When entering a large credit sale, the clerk typed in the customer’s account
number as 45982 instead of 45892. That account number did not exist. The
mistake was not caught until later in the week when the weekly billing process
was run. Consequently, the customer was not billed for another week, delaying
receipt of payment.
d. A visitor to the company’s Web site entered 400 characters into the five-digit Zip
code field, causing the server to crash.
e. Two traveling sales representatives accessed the parts database at the same time.
Salesperson A noted that there were still 55 units of part 723 available and
entered an order for 45 of them. While salesperson A was keying in the order,
salesperson B, in another state, also noted the availability of 55 units for part 723
and entered an order for 33 of them. Both sales reps promised their customer
next-day delivery. Salesperson A’s customer, however, learned the next day that
the part would have to be back-ordered. The customer canceled the sale and
vowed to never again do business with the company.
f. The warranty department manager was upset because special discount coupons
were mailed to every customer who had purchased the product within the past 3
years, instead of to only those customers who had purchased the product within
the past 3 months.
g. The clerk entering details about a large credit sale mistakenly typed in a
nonexistent account number. Consequently, the company never received
payment for the items.
h. A customer filled in the wrong account number on the portion of the invoice
being returned with payment. Consequently, the payment was credited to
another customer’s account.
i. A batch of 73 time sheets was sent to the payroll department for weekly
processing. Somehow, one of the time sheets did not get processed. The mistake
was not caught until payday, when one employee complained about not receiving
a paycheck.
q. Sunspot activity resulted in the loss of some data being sent to the regional office.
The problem was not discovered until several days later when managers
attempted to query the database for that information.
10.8 MonsterMed Inc. (MMI) is an online pharmaceutical firm. MMI has a small
systems staff that designs and writes MMI’s customized software. The data center is
installed in the basement of its two-story headquarters building. The data center is
equipped with halon-gas fire suppression equipment and an uninterruptible power
supply system.
Because the programming staff is small and the work demands have increased,
backups are only made whenever time permits. The backup files are stored in a
locked cabinet in the data center. Recently, due to several days of heavy rains,
MMI’s building recently experienced serious flooding that destroyed not only the
computer hardware but also all the data and program files that were on–site.
Required
Identify at least five weaknesses in MonsterMed Inc.’s backup and DRP
procedures.
(Adapted from CMA Exam)
10.9 Excel Problem
Create data validation rules in a spreadsheet to perform each of the following controls:
a. Limit check – that values in the cell are < 70
b. Range check – that values in the cell are between 15 and 65
c. Sign check – that values in the cell are positive
d. Field check – that values in a cell are only numeric
The ISNUMBER function tests whether the cell contains only numeric data.
e. Size check – that cell accepts no more than 40 characters of text
f. Reasonableness check – that cell’s value is less than 75% of cell to its left